I'll be upset only if you don't try. If you won't try, I can't teach you. If you don't understand, it's my fault, not yours. It's my job to teach you in a way you understand. Attempting is often more important than succeeding.
Music is a joy.
Music lessons should be fun. They are a privilege, not a punishment or a requirement. If we're not having fun, something is wrong. Piano study isn't always going to be easy, but it always should be satisfying. I emphasize initiative and self-direction.