Because he doesn't have a brain
Cuz it was yellow and appealing! Sorry if this is bad. Seen too many of the same jokes here and I wanted to add an original joke.
Jason: Two things: I got 50 in Spelling and 50 in History. Mother: Well at least you can add !
She's almost as smart as a man.
In Soviet Russia, consciousness regulates the cerebral cortex.
The hide and seek champion.
Bon'nichiwa