In "smart people" that I've met, those who perform well in quickly understanding subjects, have some sort of strong long and short term memory (something most IQ tests fail to measure) and generally read the room well, I noticed one thing: most of them are very impatient.

Whatever the task, they just want to move on, go ahead, skip over if possible and are generally awkward to be around. Those who have mastered patience are the bright ones. They also seem happier overall.