Wow OP, if I ever acted like that I'd get a nice hard slap to the face. A couple of months ago I went to the grocery store with my parents and there was this couple pushing a 4-5 year old around in a cart, and he was screaming calling everyone around him including my mom "starfishs" and "morons". I stuff you not, the parents didn't do a thing.
I just find it so weird how some parents can just let their offspring behave so badly without any sort of consequence.