When you didn't know, but you've also forgotten it!

OK, did you ever have a moment, when a genius idea comes to your mind? And you think: ' Yeah! That is very awesome indeed!' And then the next day it's completely out of your head? Erased from your mind! And you walk around the whole day with a headache trying to remember your genius idea. The only thing you only know is a shadow of the idea of which you know that it was awesome. Frustrating!