Coaches know that a parent publicly scolding his kid after a race will not help the athlete perform better.
The key to running a good marathon is to not listen to anyone's advice the last week before the race. That's when people tend to do stupid things that disrupt all the input and training of the previous months.
There's no such thing as a bad carbohydrate.
You entered a marathon with hills? You idiot.
Avoid any diet that discourages the use of hot fudge.
Grizzly bears eat people without the benefit of music.