What if I don't?

Does it matter to you if I do not do it?; What difference does it make if I do not do it? Bob: You're certainly going to tidy up a bit before going out, aren't you? Tom: What if I don't? Father: You are going to get in by midnight tonight or you're grounded. Fred: So what if I don't? Father: That's enough! You're grounded as of this minute!