Click through some of the more surprising feuds in recent Hollywood history.
Why do these famous folks not get along? For many different reasons...
Katy Perry vs. Taylor Swift
Taylor Swift wrote a song titled "Bad Blood" about an enemy in the music business. We're pretty sure the subject was Katy Perry.
Amber Rose vs. Khloe Kardashian
Khloe mocked Amber's past as a stripper. Rose fired back about Kim Kardashian's sex tape (and O.J. fathering Khloe for that matter) and this Twitter beef was ON!
Selena Gomez vs. Lorde
Lorde doesn't think Selena represents feminists very well. When you're ready come and get it? Come on, Lorde says!
Seth Rogen vs. Nancy Grace
Nancy Grace wondered aloud on Twitter whether pot was to blame for a guy killing his wife. Seth Rogen replied that the anchor is a "dumbass."
Kathy Griffin vs. Demi Lovato
Kathy Griffin thinks Demi Lovato is the biggest "douche" in Hollywood. Lovato's fans thin Griffin should shut the eff up.
Lady Gaga vs. Perez Hilton
Lady Gaga has accused Perez of stalking her. Perez has slammed the singer for thinking she's the Queen of Twitter. Ugly stuff, people.
It started in 2009 when Trump referred to O'Donnell as a "pig." She then slammed his failed marriages. Juicy stuff all around.
Drake Bell slams Justin Bieber at every opportunity. He even wants the singer deported to Canada!
Chris Brown vs. The Law
Okay, maybe this feud isn't so unexpected.
Carol Alt vs. Kate Upton
Carol Alt does not see what the "hullabaloo" is around Kate Upton. We question her hindsight.
Jimmy Kimmel vs. Kanye West
These two have sort of buried the hatred hatchet. But Kanye and Kimmel went at it over Twitter after the latter mocked the former.
Yes, Sinead O'Connor is still around. And her feud with Miley Cyrus actually ignited some interesting points about mental health.
David Letterman vs. Bristol Palin
David Letter had a lot of fun at Bristol Palin's expense when the teenager was pregnant. Some thought he crossed a line.
Naya Rivera vs. Lea Michele
Glee stars Naya Rivera and Lea Michele are reportedly beefing.
Mike Epps vs. Kevin Hart
On a radio show, Mike Epps referred to Kevin Hart as "overrated." Hart then told Epps to kill himself.
T.I. is furious with Azalea Banks, who recently took shots at his wife Tiny ... he also recently fought Floyd Mayweather over Tiny.
Sam Smith vs. Howard Stern
Stern believes the singer "looks gay." Smith simply wrote "ignore" when told of these comments on Twitter, but you just know he's seething inside.
Brandi Glanville vs. Alcohol
Okay, this isn't always necessarily a feud, as these two go well together sometimes. Things can also get ugly between them, however.
Rose McGown vs. Adam Sandler
Rose McGown called out Adam Sandler for a sexist casting note included in a movie that features the star. She did so after Sandler wore sweat pants at a public press event.
Nicki Minaj vs. Miley Cyrus
After Miley referred to Nicki as "angry" in a New York Times interview, Nicki proved her point and called her a "Bitch" on the MTV VMA stage.
Bristol Palin has a few serious things to say to Azealia Banks. Read the unwed mother's statements in response to Banks slamming Sarah Palin now.