He's as bright as a burnt out lightbulb.
You're bound to marry well - everyone is above you.
I would ask you how old you are but I know you can't count that high.
Every time he walks past a beautiful woman she sighs - with relief.
He's only got one oar in the water.
He's a gross ignoramus - 144 times worse than an ordinary ignoramus.
She's knitting with only one needle.
I've fallen into the bad habit of talking to myself. I wondered why you were looking so bored.
Some drink from the fountain of knowledge, but he just gargled.
Why don't you act like a desert and dry up.
She could even give a headache to an asprin.
Fred: I was cut out to be a genius.
George: It's a shame that the pieces weren't assembled correctly.