after you get it wrong, one of the suggestions is "why did you look at her so". Can something be done about that?
What do you mean? Done what exactly?
Why is "jste" not required here--is it because of the reflective "ses?"
Yes, instead of "jsi se" we use "ses" here. But "jsi se" is accepted as well. Not "jste", that is for the formal plural or just plural.