Exhaustion

Why do the things that bore you most and cause your eyes to become heavy always come at the worst possible time, such as when the instructor is giving a lecture to which he already passed out the entire power point, he's not putting his own words or examples he is reading the power point word for word and to top it all off no one responds on my IM client soon enough to call it a conversation so I'm floating between consciousness and passing out...someone help me...