Any scenes with Billy the Undead tend to be very humorous, right up to his reaction to seeing his own gravestone finally culminating with him delivering some truly nasty, ultimately deserved and satisfying insults at Winifred.
Billy: Wench! Trollop! You buck-toothed, mop-riding, firefly from Hell!
"I mean she really hurt my feelings! She doesn't even know me!"
"She's just jealous."
"Aaah! Burning rain of death!"
"This is ICE!"
This exchange when the sisters are at the "master's" house:
"Master": (referring to his wife) I want you to meet the little woman.
Winifred: He has a little woman!
Mary: Sounds tasty.
Max uses a "learn to speak French" tape to lure the witches into the oven. When they escape, Winnie quotes it. "Hello, I want my book. Bonjour, je veux mon livre."
"I AM CALM!!"
"Oh sister, thou art not being honesty with thyself. Huh? Huh? Come on, give us a smile."
This is one most viewers don't realize until they take a better look at the scene. After realizing Max's "burning rain of death" is just ordinary water, the sisters decide to chase after him to get the book back. The background music being played sounds like an epic chase theme... and it's just the three of them hurrying out the front door.
Sarah: "What a pretty spider..." *MUNCH*
"Oh look. Another glorious morning..........makes me SICK!"
A lot of the movie runs on Funny Background Event, and a lot of fun comes into rewatching the movie and noticing something you missed the first time due to Mary's tendency to groan and make noises, along with Sarah's fidgeting spazziness.