Because it might crack up!
or
The man says: "You go up there and tell him off. Go on, I'll hold your monkey for you."
or
Billllyuns and billllyuns. Light bulbs are part of the interstellar "goo" that pervades our universe; they are star stuff.
or
When the spider spied her!
or
Two. One to exploit the proletariat, and one to control the means of production!
or
Silly, WASPs don't screw in a light bulb, they screw in a hot tub.
or