Imagine you're in your school math class after staying up late doing homework, and the teacher calls on you to explain something complicated on the board.
Ah, there's that palm sweat everyone who's been through this is painfully familiar with.
As if woken abruptly from a dream — which, let's face it, might've been the case — you look up sheepishly at the teacher, then around at everyone else staring back at you. You squint desperately at the equation on the board, but it might as well be in some language you don't know. Maybe you try to answer it and make no sense or just sink in your seat and say, "I don't know." Either way, aside from feeling like a zombie, you're also probably left feeling pretty embarrassed.