Actual lines out of U.S. Military OERs (Officer Efficiency Report):
* Not the sharpest knife in the drawer.
* Got into the gene pool while the lifeguard wasn't watching.
* A room temperature IQ.
* Got a full 6-pack, but lacks the plastic thingy to hold it all
* A prime candidate for natural deselection.
* Bright as Alaska in December.
* Gates are down, the lights are flashing, but the train isn't
* So dense, light bends around him.
* If brains were taxed, he'd get a rebate.
* If he were any more stupid, he'd have to be watered twice a week.
* Was left on the Tilt-A-Whirl a bit too long as a baby.
* Wheel is turning, but the hamster is dead.