In a previous life, when I had a small step-son, he asked his mother if she was “happy at him.” This prompted a grammar discussion that confused him because sometimes she was “mad at him” so why was “happy at him” wrong? It stuck with me as one of those out of the mouths of babes views of life.
It prompts a bit of thought about which emotions go with which propositions. We’re happy with, but mad at. On the other hand, we can be angry with or angry at someone, but only pleased with them.
We can also be happy, glad, angry, pleased, mad, or sad, about someone.