Err....something hypothetical that definitely won't happen? That's normally a joke?

[People find things funny, when they imagine things, far more often than they do when it actually happens - Emporio Brain Logic.]

It's...mmm. It's like, if someone talked about imagining someone tripping down stairs for a laugh, they would laugh at the image, but not if it actually happened.

[That's a pretty easy one right?] Or if it was in a comedy movie, as opposed to real life. [Yeah.]