The truly ultimate responce to any kind of stupid or annoying "why" question, or simply to a question you cannot answer.
That answer will totally piss off annoying kids who ask too many questions.
See also: because you're gay.
Kid: Why did the dinosaurs die out?
Tour guide: Because you touch yourself at night.
Son: Why do you drink so much, dad?
Dad: Because you touch yourself at night!
Little brother: Why don't you ever let me into your room?
Big brother: Because you touch yourself at night, you little brat!
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.