The things he says...

C: My kleenex is on the ground.  Could you get it?
Me: Here.  Maybe you should keep it next to your pillow.
C:  That's a good plan.  You're a genius.

After Daddy told him it was time to start learning to wipe his own booty after pooping...
"I'm not gonna let you do this to me!"

Daddy:  Throw your kleenex away.
C:  But, Mommy says I can use it more than one time before I do that.
Daddy:  That makes sense.  Mommy is smart.
C:  Yep.  You're a little smart, but not as smart as Mommy.