A biology student doing his thesis on wasps is walking down the street when he passes a record store.
In the window he sees a record called "wasps of the world, and the sounds they make". Intrigued, he walks into the store. He says to the shopkeeper "I'll have that wasp record in the window please. I've been listening to so many wasps, I'll probably be able to know each and every one of them."
He smiles smugly as the shopkeeper feigns interest. The student pays and leaves. When he gets home he puts the record on.
"Bbzzzzzzzzz" it goes, but the man is stumped, he doesn't know what type of wasp this is! He waits for the next track.
"Bbbbzzzzzzzzzzzz" and again, he can't identify which species of wasp this is!
It gets to the fifth track and he breaks down. He can't identify a single wasp yet he thought he was already an expert on the subject! He calls his professor round to the house to help, when he arrives he explains to him:
"I thought I was an expert by now, but I can't identify a single wasp on this whole record!" He says, almost in tears.
The old professor ponders for a minute as he looks at the record. "Ah, I know what the problem is!" He says.
"What? what is it?!"
"You've got it on the B-side!"