A phrase used to describe complete lack of interest in what another person is saying, considered rude or necessary, depending on the conversation.
Alternatively, this can be used as a
defensive phrase, see examples, to attempt to save one's self from
ridicule.
As a
third option, it is also used as a peacemaking, forgiving phrase.
Rude-
Josh: My grandfather passed away this morning.
Jake: So what?
Necessary:
Josh: Oh my god, I think my
shoelace is coming
undone!!!!111oneone!!!
Jake: ...so what?
Defensive:
Josh: You're an ass, man.
Jake: So what?
Forgiving:
Josh: I'm sorry I called you an ass.
Jake:
Forget about it, man. So what?