Changing a Light Bulb with Abused Children Is Not Enough to Impress a Drunk Father?! Huh?! What a Twist!! 

Listen here, you dum-dum. You're probably the kinda person who thinks mayonnaise is spicy. This "joke" is playin' on somethin' dark: child abuse and neglect. The setup asks how many abused kids it takes to do a simple task, but the punchline is that no matter what they do, they can't please their drunken dad. It's morbid 'cause it's findin' humor in a terrible situation.