Great post - I've heard almost all of these from various parents.
At my son's signing in March, we invited a couple of former coaches. I was thanking one of them and sharing about our baseball experience through son's life. He's truly never had a negative experience (with one exception of a recruiting experience last fall) in baseball. To make a long story short, the coach said that much of our happiness and joy with baseball was due to my son's attitude. I thought about this for a few days and he's probably right. Those parents that support not only their son, but the coach (don't mean kissing butt) and teach their child the values that Coach May and Sandman have talked about will have a much happier, successful, and fulfilling experience. The kids who I've seen have an attitude have usually been reflections of their parents. While those kinds of parents mentioned above are frustrating to say the least to coaches, they are really doing their child an even bigger diservice.
Bulldog - I'm afraid I am one of those parents yelling suggestions from the stand. I'll have to say I really have very limited baseball skill knowledge - I do it as a way to cheer. Or I thought it was a way to encourage and cheer! My son's favorite is "don't overthrow".
I've stopped all of the advice this year as I realized he doesn't need my suggestions for many reasons!!! He had to help me realize this one!!