"A collection of insults 37" joke

Fog rolled in the day he was born, and a bit of it never rolled out.

Folds ace plus red jack hand when playing blackjack.

Foreign substances float in his cranial fluids.

Forgot to pay his brain bill.

Found his marbles, but is playing jacks with them.

Four bits shy of a full DEC.

Four cents short of a nickel.

Full of wisdumb.

Full throttle, dry tank.

Fur coat and no knickers. (Scottish expression.)

Gasoline engine, diesel fuel.

Gates are down, the lights are flashing, but the train isn't coming.

Gavel doesn't quite hit the bench.

Gears grind/don't always mesh.

Gets her mail at an unknown zip code.