I have a large group of gifted students this year.  They have developed a bad habit of racing through their assignments, so I've been getting on them about slowing down and checking their work...

Mrs. B:  (looking over a student's assignment)  Hmmmm...

Caleb:  What?

Mrs. B:  Well, you've made a lot of mistakes here.  I wonder why?

Caleb:  (mirroring my sarcasm)  Maybe it's 'cause I'm not that smart after all.