We've used it as a short response to Mom who told us something like "oh, I see you're not wearing very many clothes to school today" or "don't you think you're...uh... hangin' out of that top a bit?" as we came down the stairs for breakfast one morning.
We've used it to leave our options open, or to escape making a decision. "What do you guys want to do tonight?" Then, "Whatever! It's up to you."
We've used it to expose the trivialness in the obviously ridiculous statement someone just made. "Okay, WHAT.EVER. That doesn't even make sense!"
We've used it to deflect a personal attack. "I think you're being ridiculous right now." "Whatever."
Here's urban dictionary's take"
Whatever
A polite and less vulgar alternative to "FUCK YOU".
Jack: "Wow, what happend to you? You look like hell today!"
Jill: "Whatever"
I'm sure you've heard it a million different times in a million different ways. But the point is, what does "whatever" really mean? It's one of the few words that been so stripped of its denotational value and is almost always evaluated based on its connotation whenever it's used in a sentence.
I don't know about you, but whenever some one says, "Whatever" and that's it, a red flag goes up. Time to negotiate, time to try and cheer them up.
So is that what it is? A plead for something more?
I don't know.
Whatever.