Why, because they won't get off your lawn?
The Big Bang Theory Season 8, Episode 4
Well, when you realized what it was,
WHY didn't you stop?
The Big Bang Theory Season 9, Episode 9
Yeah, but WHY are you fat?
The Big Bang Theory Season 7, Episode 11
Why?
Game of Thrones Season 3, Episode 8
Why not?
Breaking Bad Season 4, Episode 7