ETA: Thanks for everyone's feedback. I see that most of my opinions differ from the general consensus, but I stand by mine and respect yours. (Though in hindsight, Dying For Pie should have been higher on the list and KKTV and Wet Painters should've been in there somewhere. Oh well.)

ETA x2: I will fix this by providing a list of honourable (and dishonourable) mentions:

Good:
Krusty Krab Training Video
Wet Painters
Doing Time
The Sponge Who Could Fly
Squidward, The Unfriendly Ghost
Sleepy Time
Fear of a Krabby Patty
Shell of a Man
Ugh

Bad:
The Two Faces of Squidward
Growth Spout
Skill Crane

...Yep, I think that's it. I don't really hate that many episodes.