First off: This list isn't meant to offend. Some of these are academy award winning roles! But others are just… bad. Judge for yourself. All I know is Rosie's 'Riding The Bus With My Sister' trumps all.
1. Rosie O'Donnel in 'Riding The Bus With My Sister'
The best movie ever.
2. Leonardo DiCaprio in 'What's Eating Gilbert Grape'
3. Sloth from 'Goonies'
4. Billy Bob Thorton in 'Slingblade'
5. Hanson from 'Scary Movie 2'
6. Tom Hanks in 'Forrest Gump'
7. Kristen Stewart in 'The Cake Eaters'
8. Jon Heder in 'Napoleon Dynamite'
9. Warren from 'There's Something About Mary'
10. Cuba Gooding Jr. in 'Radio'
11. Dustin Hoffman in 'Rainman'
12. Booger from 'Revenge of the Nerds'
13. Molly Shannon in 'Superstar'
14. Sean Penn in 'I Am Sam'
15. Hank from 'Drop Dead Gorgeous'
16. Adam Sandler in 'Billy Madison'
17. John Malkovich in 'Of Mice And Men'
18. Elizabeth Shue in 'Molly'
19. Juliette Lewis in 'The Other Sister'
20. Robin Williams in 'Jack'