Idiot Box was hilarous, and House Fancy wasn't that bad. I liked the climax of it. The toenail part of it was gruesome and disgusting though.
The Splinter actually scared me a little. I changed the channel when it got to that big gruesome blob of goo. Then when I finally did watch it, it exploded into confetti?
Also, I suppose The Krusty Towers was a good episode. It had decent jokes, unlike the new episodes.
The worst episodes in my opinion are the "Spongebob Legends" series of tales from Season 7 or 8. Not The Patty Gadget, the ones with Madame Hagfish and stuff. The jokes in them are bad and Madame Hagfish is ugly.
Also the episode where the gentlefish come to the Krusty Krab and close it.