I definitely know what you're talking about. I have no problem helping people but on occassion I have to give help to someone who has absolutely no idea what I'm trying to explain, then gets frustrated because they don't understand and it gets ... difficult.

My brother comes to me for every problem he has with a computer, even down to a silly little thing he could easily fix himself if he just just tried.

BUT ALAS, THIS IS THE LIFE WE CHOSE!

...so to speak...