One of my sisters, years ago, said that her son was much better mannered after I made the comment that "NO one ever loves a brat". And when he gets in school the other kids will smack the tar out of him, they have ways of getting even with brats.
She started training him at about 3 years old and he's the most charming gentleman you can imagine at age 44 or so. And he's also a guard in a prison, so he's not a meek guy either.
My youngest daughter tried the screaming and hurling herself on the floor and holding her breath. I simply dumped the water from a vase of flowers on her head and stood there, clapping at her antics. She got so mad at that she got up and sulked in her room for a while, then came out all friendly again.