I'm totally ungrateful
Oh is that so? Why do you say you are ungrateful?
I'm whining that my mom didn't buy me a car for a graduation gift.
You shouldn't be so ungrateful. Your mom supported you throughout your studies. You should be thanking her.
NO! I'm going to complain and say she never loved me.
That's a bit rude to your mother don't you think? You should be happy for anything that she buys you, presents are never guaranteed in any situation.