Movie stars get paid unimaginable amounts of money to act in films, while flying to exotic locations and having people lavish them with lots free goods and telling them how get they are.
But it seems they have very fragile egos, and sometimes, when two stars' ego's collide, it can be a explosive and destructive issue.
Take for instance these examples...
10. Bill Murray tells Lucy Liu she can't act, fists start flying
While filming the first Charlie's Angels film, Bill Murray was always visibly uncomfortable around Lucy Liu, which baffled everyone as to why.
It all came to a head while shooting a scene; Murray stopped mid-scene and pointed to the Angels, saying: “I get why you’re here (Drew Barrymore), you’ve got talent (Cameron Diaz)… but what in the hell are you doing here? You can’t act!"
Murray's comment made Lucy Liu flip her lid as she flew towards Murray throwing punches, before both actors had to be separated to opposite corners of the room while still shouting and hurling insults at each other.
When the Charlie's Angels sequel was made, Murray was recast with Bernie Mac (probably as they couldn't replace Liu as a main Angel).
In recent years, Bill Murray has tried to explain/lie about what he actually said.
"We began rehearsing this scene and I said, 'Lucy, how can you want to say these lines? These are so crazy'.
"She got furious with me because she thought it was a personal assault, but the reality is she hated these lines as much as I did... I feel very warmly for her now."
9. Kim Cattrall refuses to be in Sex and the City movies until she's paid as well as Sarah Jessica Parker
When the hugely-successful TV show was making the jump to the TV show, Kim Cattrall thought the salary that was offered to her and fellow co-stars Cynthia Nixon and Kristin Davis was insultingly low compared to 'main' star Sarah Jessica Parker.
Cattrall's refusal to sign up for the first movie over pay check rows held up development of the film, eventually agreeing to star as Samantha for $6m (with Nixon and Davis picking up 'only' $2m) for the first movie
Sarah Jessica Parker was no innocent party in the rows either, without revealing too much, Parker explained to Marie Clare: "When you're on set, you're working 90-hour weeks, you're never home, you're exhausted.
"There are times when all of us have been sensitive and sometimes feelings get hurt. But I don't have any regrets about how I've treated people."
Perhaps SATC fans will never find out the extent that the onscreen best friends fell out.
8. Harrison Ford and Josh Hartnett refuse to speak to each for hours in between takes
While filming the 2003 action comedy, Hollywood Homicide the pair spent many frosty times on set.
Hartnett explained: "There were times we would end up just sitting in the car when we were supposed to be doing a scene and neither of us would say anything for like an hour."
Hartnett also revealed that the pair allegedly fought throughout the entire process, Ford called Hartnett a 'punk' and Hartnett replied, labelling Ford an 'old fart'.
Even after shooting had finished, the pair bickered while on the film's promotional tour.
7. Val Kilmer flips out over Tom Sizemore's elliptical machine
While filming the sci-fi flick Red Planet in Australia, Val Kilmer went mad when he heard that Sizemore had production pay for his elliptical machine to be shipped Down Under from the UK.
Kilmer flipped out on his on-off friend, shouting: "I'm making ten million on this; you're only making two!" Sizemore then threw a 50-pound weight back but missed.
Kilmer then refused to say the name of Sizemore's character, replacing it by shouting "Hey you!"
By the time the filming was nearing completion Kilmer refused to step foot on set if Sizemore was around and the director resorted to shooting the rest of their scenes over the shoulders of doubles.
6. Jamie Foxx throws a hissy fit with Colin Farrell's paycheck, refuses to work outside the USA
Fresh from his Oscar-winning success with Ray, Jamie Foxx rolled onto the set of the ill-fated Miami Vice reboot with an entourage and demands.
The star refused to fly a commercial airline to Miami and Universal had to give him a private jet, and when Foxx found out that his co-star Colin Farrell was getting a higher salary, he demanded more - and secured a large raise.
It didn't stop there; while shooting in the Dominican Republic, director Michael Mann used a private security force to protect the cast and crew while working in an especially unsavoury part of Santo Domingo, the Caribbean nation's capital.
When a police officer approached the set, he got into a fight with a guard and was shot and wounded.
With that, Jamie Foxx flew straight back to America and the star refused to film anything outside of the US.
Mann had originally planned the film's finale to be set in Paraguay, but had to change the plot at the last minute for Foxx's demands, resulting in a rushed and disappointing climax to the film.
5. Shia LaBeouf knocks out Tom Hardy (probably)
The pair aren't the most shy and retiring of film stars, so when they were united for bootlegging tale Lawless, sparks flew between the pair.
To get into character, LaBeouf drank moonshine which made him aggressive and the pair had a tussle and LaBeouf claims that Hardy "never did that roughhouse stuff with me again."
While everyone was trying to get more info about the scrap, Tom Hardy revealed that the Transformers star had actually knocked him out.
Speaking to disbelieving journalists, Hardy explained: "No, he did. He knocked me out sparko. Out cold. He's a bad, bad boy. He is. He's quite intimidating as well. He's a scary dude."
The muscle-bound Mad Max star's protests are so vehement, it almost seems as though LaBeouf paid him to say that.
4. Tommy Lee Jones is not a fan of Jim Carrey's buffoonery
Appearing as The Riddler and Two Face, nemeses of the caped crusader, Tommy Lee Jones and Jim Carrey were a perfect double act in Batman Forever's campy superhero fun.
According to Jim Carrey, perhaps Jones was still smarting from Carrey's Dumb and Dumber trampling all over Jones's Cobb and Cobb in the box office.
When Carrey went to say hello to his co-star on the Batman Returns set, "he got kind of shaking and hugged me and said, 'I hate you. I really don't like you.'
"I was like, 'Wow, okay, what's going on, man?' And he said, 'I cannot sanction your buffoonery.'"
Despite this, Carrey's unsanctioned buffoonery went down well with Batman fans with memorable performances from both warring co-stars.
3. Richard Dreyfuss constantly bullies Robert Shaw on Jaws set
Steven Spielberg’s legendary shark movie suffered well-publicised production issues, especially a titular shark that frequently malfunctioned, resulting in the great white's diminished screen time (which may have helped with the tension).
As well as that (and more), the film's two main (human) stars, Robert Shaw and Richard Dreyfuss didn't get along in the slightest.
Hard-drinking Shaw took an exception to the younger Dreyfuss and would repeatedly antagonise his co-star, criticising his weight, with comments like: "you couldn’t even do ten push-ups, at your age, it’s criminal."
Dreyfuss was driven mad by the frequently-drunk Shaw's goading, so much so, that at one instance Dreyfuss grabbed his co-star's drink out of his hand and threw it overboard.
Steve Spielberg didn't mind too much, as he felt their characters' spiky relationship was aided by their off screen clashes - here's a video of Spielberg, Shaw and others involved in the film chatting about the behind-the-scenes battles.
2. C-P3O berrates R2-D2 for saying 'hello' to him
The legendary droid duo provided some of the light-relief in George Lucas' space soap opera series, but C-3PO and R2-D2's real-life counterparts aren't as inseparable as the droids.
According to Kenny Baker, who sits inside the R2-D2 character, his C-3PO co-star Anthony Daniels is the rudest person he's ever met.
One time on set, Baker had the audacity to greet Daniels on set, to which Daniels gave a less than friendly reply.
"Once when I said hello to him he just turned his back on me and said, ‘Can’t you see I’m having a conversation?’ I was blazing with rage," the actor revealed.
“It was the rudest thing anyone had ever done to me. I was furious. It was unbelievable."
Baker also explains that Daniels treats everyone in the film series with the same amount of contempt, and doesn't socialise with any of the cast or crew, which suits Baker fine.
“By the time Anthony is in his costume I don’t see him.
"I turn up five minutes before filming starts and they pop me into the R2-D2 shell. There’s no talking once you’re inside.
“He’s had 30 minutes getting out at the end and by that time I’m away. We never meet socially–we don’t live anywhere near each other."
1. Sylvester Stallone starts Richard Gere's 'gerbil' rumour over a mustard stain
One of the most (in)famous Hollywood rumours reportedly emerged from the (slightly crooked) mouth of Sylvester Stallone - that of Richard Gere's fondness for *ahem* gerbil insertion.
"He would strut around in his oversized motorcycle jacket like he was the baddest knight at the round table," Stallone said of his co-star's behaviour while filming the 1974 flick The Lords of Flatbush.
Sly also revealed that their on-set animosity started over a mustard stain.
"I was eating a hot dog and he climbs in with a half a chicken covered in mustard with grease nearly dripping out of the aluminum wrapper,"
"I said, 'That thing is going to drip all over the place.' He said, 'Don't worry about it.'
"I said, 'If it gets on my pants you're gonna know about it.' He proceeds to bite into the chicken and a small, greasy river of mustard lands on my thigh.
I elbowed him in the side of the head and basically pushed him out of the car. The director had to make a choice: one of us had to go, one of us had to stay."
Stallone demanded that directors Martin Davidson and Stephen Verona push Gere off the project, which they did, sacking Gere.
The Rocky star also stated that Gere thinks he started the gerbil rumour, but Sly is quick to deny it came from him.
Who knows the truth? Gere, Stallone and some unfortunate rodents, probably.