I remember reading about a study done about university athletes and their parents involvement in their youth sports... The two takeaways were this:
1. no critical feedback...zero, zilch, nada...regardless of how they played
2. Telling their kids that they love watching them play
These 2 things led to positive associations with sports and high intrinsic motivation...I have vowed never to say a negative thing about my kids play...I can leave that for the coaches.
100% agree