On page 9 it says I don’t remember touching her, but the next thing I knew, Nancy was sitting her butt in the fountain, screaming, “Percy pushed me!” Percy’s choice is to push Nancy, and this makes him into trouble and also made Grover worried about him and his choice made Ms. Dodds have a good reason to take Percy away from their class, and because of all this everyone lost the memories of Ms. Dodds like she has never exist before, and it actually didn’t affect Nancy even she is mean and Percy just got himself into trouble and Nancy seems to be doing nothing at all. Also it make Grover worried about Percy, he even tried to lie to Ms.Dodds just try to save Percy but it didn’t work.
I think Percy didn’t have a positive action to help him manage his emotions, he can fix that by being kind to other student/classmate in his school and that will help his stop being worried about himself.
Also, I think Percy can have many different ways solve this problem. For example, If Nancy Bobofit dumped her half-eaten lunch at Grover Percy can did the same thing to her and if she cried or yell and while the teacher came he could just say that he didn’t mean it and it was just an accident so he won’t get into trouble again. Or he can just tell the teacher or walk away with Grover.
Those are my point of Percy didn’t make a good choice.