Life is too short to hold grudges, but that doesn’t seem to stop us from doing it anyway. If someone hurts you, it’s just so much easier to hate and ignore them than it is to sit and work it out. We can hold onto grudges for years, and even though we know it’s not ideal, it seems like the right thing to do.

The reality is that pettiness and holding on to the past can have a terrible impact on your mental health and most of us eventually learn that, although it’s hard, forgiving and forgetting really makes life a lot more bearable. Spending your time spreading negativity is really a waste, it’s so much better to just move on.

But there are some celebs for whom it seems learning this simple life lesson will never be possible. They seem to get their thrills from engaging in petty passive-aggressive tiffs with each other over the silliest things and it leaves the rest of us just shaking our heads. Could it be because they don’t have enough real-world problems that they need to create all this extra drama in their lives? We can’t say, but what we can tell you is that these 15 celebrities totally hate each other and here’s why:

Julia Roberts Can’t Stand Nicole Kidman’s Diva Like Behavior

When two accomplished actresses come together to work on a movie, it can go one of two ways. Either they hit it off, or they don’t. When Nicole Kidman and Julia Roberts worked together on the 2015 film Secret In Their Eyes, they did not gel well together at all and according to the National Enquirer, it all has to do with the way that Kidman treats the crew. Apparently, Julia can’t stand Nicole’s diva-like behavior and the fact that she won’t even talk to people on set who she considers lower than her. A source from the set told National Enquirer said "Julia HATES the way Nicole treats the crew! She acts like they’re servants, and doesn’t talk to them – except to issue commands – while Julia now knows everyone by first names, and makes a point of being friendly."

Sylvester Stallone Thought Bruce Willis Was Too Greedy

What started the feud between Bruce Willis and Sylvester Stallone was when, after appearing in the first two films of the Expendables franchise, Willis demanded a whopping $4 million for four days on the set of the third movie. Sly felt that a $1 million a day was slightly over the top and he took to Twitter to voice his annoyance. “Greedy and lazy…A Formula For Sure Career Failure,” he tweeted and a rep later confirmed that the tweet was aimed at Willis. Bruce subsequently didn’t appear in the film, but the two have since buried the hatchet. Stallone tweeted: “Made up with Bruce W. A stand up guy, my mistake….”At least these two were able to be grown-ups, which is a lot more than we can say about some of the other celebs on this list.

Lindsay Lohan Felt Amanda Bynes Got Special Treatment And She Didn’t Like It

Amanda Bynes and Lindsay Lohan are both well known by the paparazzi for the hard-partying lifestyles and brushes with the law, but just because they are both rebellious doesn’t mean that they are friends. In fact, Lindsay was apparently furious when she faced real jail time for her repeated misdemeanors and expressed her dissatisfaction with the way that Bynes had been treated in comparison. She tweeted about the alleged injustice saying, “Why did I get put in jail and a Nickelodeon star has had NO punishment(s) so far?" Aww, it’s not fair. Welcome to the world Lindsay – get used to it. According to insiders Bynes hates Lindsay too, almost obsessively, and talks about her all the time. This feud is so silly and childish, but what more would we expect from Hollywood?

Justin Bieber Vs Orlando Bloom

We know that Orlando Bloom and Justin Bieber definitely won’t be sending each other Christmas cards this year but do you know what sparked this intense celebrity rivalry?

Here’s the story: Back in 2014 Bieber and Bloom met each other while on holiday in Ibiza and it wasn’t long before a fight erupted. Justin apparently made remarks about Bloom’s ex-wife Miranda Kerr and insinuated that the two of them had been intimate while she was still married to Orlando. The Pirates of the Caribbean star did not take this well and took a swing at the singer (and missed) before security stepped in to try and de-escalate the situation. Later that day Justin mocked Orlando by posting a picture on social media of the actor crying, and since then the two have been sworn enemies.

Bette Midler Does Not Approve Of Kim Kardashian's Selfies

We’re sure that by now Kim Kardashian must be used to the haters who constantly try to take her down a notch on social media. But that doesn’t stop her from occasionally firing back at them and when she does we all like to sit back and watch the drama unfold. And in March 2016 we were treated to one of her most entertaining showdowns yet with none other than singer Bette Midler. Midler (71), who is very active on social media, took offense when Kim uploaded a racy nude selfie on Twitter, apparently in yet another attempt to break the internet. Midler responded by tweeting, “Kim Kardashian tweeted a nude selfie today. If Kim wants us to see a part of her we've never seen, she's gonna have to swallow the camera.” Burn! Not to be outdone (or so she thought) Kim responded with “hey @ BetteMidler I know it's past your bedtime, but if you're still up and reading this send nudes # justkidding."

Katy Perry And Taylor Swift Are “Straight-Up Enemies”

So we all know that Taylor Swift’s hit song Bad Blood was written about a fellow pop star who crossed her and it doesn’t take much to work out that the subject of the song was, in fact, Katy Perry. The two have one of the most well-documented celebrity feuds, but it’s not clear, even to Taylor, if they ever were friends, to begin with. “For years, I was never sure if we were friends or not,” she said, “She would come up to me at awards shows and say something and walk away, and I would think, ‘Are we friends, or did she just give me the harshest insult of my life?’" But when Katy started dating Taylor’s ex John Mayer, a line was drawn in the sand and now according to Taylor they are “just straight-up enemies”.

Eminem Wants Mariah Carey To Admit They Had A Relationship

Mariah Carey has been romantically linked with a number of celebrity men, but she hasn’t always been completely open about her relationships. She denies ever having had a relationship with Eminem, for example, and he hasn’t taken this snub well at all. The pair have been locked in a passive-aggressive feud for years; he dissed her with songs like “The Warning”, while she’s steadfastly maintained that their relationship never went further than a professional liaison. Back in 2001 the pair allegedly starting dating after meeting to discuss a possible collaboration, but by 2002 Eminem was mentioning the diva in his song Superman, rapping “What you trying be? My new wife? / What, you Mariah? Fly through twice”. But just what really happened between these two is anyone’s guess.

Christina And Kelly’s Big Fat Feud

Christina Aguilera and Kelly Osbourne have been at each other’s throats for years. In fact, their hatred for each other started way back in 2003. Kelly openly mocked Christina’s Christmas CD on The Osbourne’s and the singer did not take kindly to that. Later that year she got her revenge when she publicly taunted and humiliated Kelly at the MTV Movie Awards, calling her fat. And since then it’s been on – with slights and insults being hurled back and forth between the two. You’d think that at least one of them could have managed to let it go, but no, forgiveness does not appear to be in their vocabulary. And even worse, they seem to thrive on each other’s struggles. When Christina gained a lot of weight around 2011, Kelly was apparently delighted and felt that it was payback for the singer’s mean commentary on her own weight.

Were Gwyneth Paltrow And Madonna Just Too Much For Each Other?

There was a time when Madonna and Gwyneth Paltrow were BFFs, but these days they ignore each other completely. And since neither of them is willing to shed any light on why they are no longer friends, we can only speculate as to what happened.

Paltrow once said that Madonna was “like an older sister to her” but the pair mysteriously cut off contact with each other in 2010 with no explanation. Some people believe however that Gwyneth may have made reference to this tiff in a magazine interview later that year when she said, “I can be mean. I can cave into gossip. I can ice people out and I can definitely harbor revenge. In fact, I’m having a situation right now with a friend where I’m feeling pretty angry." Do you think she was talking about Madonna?

Russell Crowe Took A Swipe At George Clooney For Doing Ads

What do you think about celebrities who use their status to earn money with advertising? Do you think it’s just wrong to see an actor advertising suits or watches or do you think it’s a legitimate way to use their celebrity? The celebs themselves seem a little torn over this issue, but Russell Crowe is not one of them. He believes it’s wrong, and during an interview in 2005, he took a swipe at leading men who do ads. “I don’t use my ‘celebrity’ to make a living," he said, “I don’t do ads for suits in Spain like George Clooney, or cigarettes in Japan like Harrison Ford … To me it’s kind of sacrilegious — it’s a complete contradiction of the f***ing social contract you have with your audience. I mean, Robert De Niro’s advertising American Express.” He later apologized for this statement, but George Clooney wasn’t so quick to back down and reportedly told Crowe, “Dude, the only people who succeed when two famous people are fighting is People magazine. What is wrong with you?”

James Franco Doesn’t Have Time For Anne Hathaway

Can you imagine James Franco and Anne Hathaway hanging out together? No neither can we. But you would have thought that Franco would have at least tried to defend his 2011 Oscar co-host when Howard Stern spoke unfairly about her but he didn’t. After Stern said, "Everyone sort of hates Anne Hathaway, and I've explained that I do too and I don't even know why sometimes. She's just so affected [and] actress-y that even when she wins an award she's out of breath, and then she has the standard joke that sounds like it's [been] written [for her]. And it all seems so scripted and acted.” Franco simply responded by saying, "I'm not an expert on -- I guess they're called 'Hatha-haters'-- but I think that's what maybe triggers it." Nice one, Franco.

Shia LaBeouf Felt Alec Baldwin Couldn’t Keep Up With Him

Alec Baldwin and Transformers star Shia LaBeouf were meant to star alongside each other for the revival production of Lyle Kessler’s play Orphans, but Shia was let go from the play due to “creative differences”. According to a first-person article written by Baldwin, the reason that Shia was booted from the production was because of his “entitled” attitude. He says that Shia showed up flustered for rehearsals and although he knew his lines off by heart he quickly grew frustrated when others "couldn’t keep up with him”. Baldwin went on to say that Shia had verbally attacked him in front of everyone shouting, “If you don’t say your lines. I’m just going to keep saying my lines.” Baldwin offered to leave the production, but the executives thought that the show could do without Shia and fired him instead.

Clash Of The Egos: Nicki Minaj Vs Mariah Carey

American Idol should have known that the egos of Nicki Minaj and Mariah Carey could never fit into the same room together, but they put them together as judges in 2013 anyway and it wasn’t long before the catfighting began. The pair got into a heated argument when Nicki criticized Mariah for being too harsh with one of the contestants and Mariah responded by saying, “I’m sorry, it’s just that that’s what I do, Nicki.” Minaj, who is properly not used to people talking back to her, exploded shouting, “Oh, you’re right. I’m sorry I can’t help her. Maybe I should just get off the panel! Let me get off the panel!” before storming off in a big huff. Minaj called later called Carey a "bitter, insecure woman" and said that working with her was like working with Satan in hell. Shoo, it couldn’t have been that bad Nicki, maybe you should try an office job before you complain.

Perez Hilton Said He Was Attacked – But Will.i.am Said He Was Insulted First

So we’re not sure what Perez Hilton thought would happen when he started poking his nose around in celebrities private lives, but he couldn’t have expected that they would just welcome him into their ranks with open arms, did he?

Back in 2009, Perez shocked the world when he tweeted that he had been assaulted by Black Eyed Peas manager Liborio "Polo" Molina after he and Will.i.am got into a heated argument outside a nightclub. Now it’s hard to tell who was telling the truth, but instead of calling the police to report the assault Perez took to social media to tweet about the attack instead. Hmm. Then followed a string of videos and response videos in which Will alleged that he had approached Perez with respect and had been met with a homosexual slur. Perez later admitted to this but called it misguided. Honestly? We’d have to side with Will on this one, Perez is just too unbelievable at times and we don’t think he’s beyond fabricating stories to further his own popularity.

George Takei Says William Shatner Is Not A Team Player

After acting together so closely for so many years you would think that George Takei and William Shatner would be buddies, right? Well, we hate to shatter your illusions about Star Trek camaraderie here but this couldn’t be further from the truth. From what we can gather the two just never hit it off, Shatner says that he never really took the time to get to know George. When asked about the animosity between them Takei said that it is driven by Shatner. “It's all a matter of ego,” he said, "It’s difficult working with someone who is not a team player. The rest of the Star Trek cast all understand what makes a scene work — it's everybody contributing to it. But Bill is a wonderful actor, and he knows it, and he likes to have the camera on him all the time."