Click through some of the more surprising feuds in recent Hollywood history.
Why do these famous folks not get along? For many different reasons...
1. 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.
2. 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!
3. 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!
4. 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."
5. 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.
6. 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.