You bend down to do a line, move along it only to realize your tube is 6 inches away from the line.
You hold your phone/mp3 player 2 inches from your face an rotate it around to try and make sense of whats on the screen
You suddenly think of a great song to listen to, open up your list of tracks an start scrolling down only to get to the bottom of the list and realize you have no idea what you were looking for.
You start start rolling a cigarette, forget, look at your lap 5 minutes later an realize you're covered in tobacco.
You've been happily trying to smoke a stick of filters for the last 10 minutes.
You're having a conversation with your friend sat next to you, you mention something that only they know, they say "what", you turn to look at them and realize you're talking to someone completely different
Lols, guna try and think of more