Lest I leave you with the impression that teenagers are pure evil, here's a cute routine courtesy my fourteen year old math student, Rico Suave:

Rico: "Miss P, do you want two tickets to the gun show?"

Me: "Eh? Um, sure?"

Rico: *pulls up sleeves, flexes biceps*

And a variation on same, courtesy seventeen year old Tubby (note that Tubby is not actually overweight):

Tubby: "Miss P, do you have any thread?"

Me: *absentmindedly* "And why do you need thread?"

Tubby: "Cause I was flexing my guns, and I ripped my sweater!" *shows off hole in sweater*