Math

Colby: "Mom, we're learning about division at school, and I'm the only person in the whole class who gets it."
Mom: "Really?  Good job!  What about Quinn?  Doesn't he understand division?"
Colby: "Well, actually, I guess he does, because I taught him in the shower last night."
Quinn: "I forgot.  I don't get it."
Colby: "You CAN'T forget it!  I taught you!"

Here's Mom, chuckling at the irony of that sentence.  How many times have I taught you to use a fork when you eat???