An explosive punchline
Babies
Aren't all cats pure evil
Ask him what color the blue line is and wait. It may take him ten minutes to answer.
You won't be able to tell witch witch is witch.
It's a touchy subject.
Because it's two gross! (A gross is a measurement unit for "144". So 2 * 144 = 288. Or "two gross".)
The way that the punchline of the joke is delivered.