A brief synopsis... When you're at a loss for words but want to tell someone that he or she is stupid, remember some these quips from our collection here at Aha! Jokes.
A few beans short of chili.
A few beers short of a six-pack / a six-pack short of a case.
A few birds shy of a flock.
A few blocks short of a filesystem.
A few bombs/melons short of a full load.
A few bricks short of a wall / hod / load / pile.
A few chips short of a cookie.
A few clowns short of a circus.
A few clues shy of a solution.
A few cold solder joints.
A few ears short of a bushel.
A few feathers short of a whole duck.
A few few cylinders short of a full re-format.
A few fish short of a string.
A few french fries / one hamburger short of a Happy Meal.