As a coach, you do not yell out loud to a player on the field and tell her she "messed up". You are then making an example out of her to the entire team and people on the sideline. when these players get to the recruitment age, do you really want to yell out that they messed up in front of a sideline of college coaches? You wait for an opportunity to sub for her and explain to her what she needs to do to correct her mistake. If you constantly yell at players for making mistakes then they will not take risks on the field for fear of being "singled out". Coaching 101.
