A renowned, white-haired scientist sits at his desk and sighs. He pulls open a drawer, removes a snub-nosed revolver and puts it to his head. At that moment, his younger colleague bursts into the office and slaps the gun from his hand. It hits the floor, spins uselessly on the floor like a top, then stops. Just to be safe, the young man walks over to the gun, picks it up and puts it in his pocket.
"What the hell are you doing?" the young man shouts.
The old man sighs, gets up and goes to the blackboard. He picks up a piece of chalk and writes an equation. The younger scientist studies it.
"Oh," he says.
The elderly scientist nods, picks up an eraser, and obliterates the equation. He returns to his desk and sits back down. His younger colleague takes the gun from his pocket and hands it back to him. The elderly scientist nods politely, then blows his brains out. The young man studies him for a moment, sighs, then walks over and picks up the gun.
And blows his own brains out.