Whatever can mean "I don't really care" (example 1)
Whatever can also meant "Fuck You" (example 2)
PERSON 1: Where do you want to go for dinner?
PERSON 2: Whatever, i'm not really hungry?
PERSON 1: It's you're fault we got pulled over last night.
PERSON 2: Whatever, if you would have just let me drive then we would have made it home no problem.