Besides, it's no fun being silly if everything is silly.
If an ordinary businessman is walking down the street, and abruptly a strange woman in a red wig comes running up and slaps him in the face with a trout, that's funny.
If the man is an anthropomorphic pie, and the street is made of golden coins, and the man is carrying a walrus wearing a tophat, and it's raining Butterball turkeys, then the troutslap loses a lot of that raw edge of humor.
The exception, as always, is
Twisp and Catsby.
Further Research