These are the reasons why:
EVERYONE'S HAIR WAS TOO LONG. Ron looked like Shaggy from Scooby-Doo, and Harry looked like a girl.
MOANING MYRTLE IS A PERVERT. She literally tried to rape him in the bathtub. Eewww... :x
DUMBLEDORE HAD ANGER ISSUES. He started calming down in OOTP, and HBP he was back to normal.
DURMSTRANG AND BEAUXBATONS ARE SUPPOSED TO BE CO-ED. Thanks a lot, Mr. Newell, for approving sexism in the HP movies. :scream:
LACK OF GOOD DIALOGUE. Examples: "I Love Magic!" (thank you, captain obvious...) "I'm not an owl!" (We know that, Hermione...) "Now, I can touch you!" (Voldemort is a pervert, too.) And don't get me started on "Do The Hippogriff," the worst song about magic ever penned. :evil:
TOO MUCH SLAPSTICK HUMOR. HBP had just enough, since HBP is the funniest book in the series. GOF, however, fails in every attempt at funny. Madame Maxime trying to clean Hagrid's beard with her mouth? Fail, and disgusting. Hagrid stabbing Flitwick with a fork? Fail, and discrimination to vertically challenged people. Snape whacking Harry and Ron was actually worthwhile...
VOLDEMORT WAS THE BEST THING ABOUT THE MOVIE.
This morning I threw up, fell asleep for 4 hours, went to the bathroom, drank some orange juice, fell asleep for an hour, drank some water, fell asleep for 5 hours, watched "Surf's Up" (which I highly recommend,) went on the internet, watched TV, and went on the internet again. I feel miserable.....