Should we say good or excellent when someone is right? Depends on who the person is and number of interactions with them and the outcome we expect.
If a parent, we would want to say only good to our child to keep him grounded yet appreciated. If we are appreciating a friend, we would say excellent, because we don’t have to hold back or strategize when appreciating him. If a team member, we would say good or excellent based on the magnitude of work completed or achieved.
Analyse the difference in approach towards each of them. Why this difference? Its because we are more or less or not concerned about people in our lives.