Don't swear at 14 yr old refs in front of 7 yr old hockey players. Yes, my son's coach actually did this when my son was 7.
If you're too lazy to write down what time your kid gets on and off the ice, then don't complain to the coach that your son is underplayed. Or daughter.
On the other hand, if your son is on the bench most of the game, then start writing down the times he gets on and off the ice. I was parent rep on a house league team where the coach was playing one kid less than 5 minutes per game, while the coach's son played 15-20. The parent never said a word all year.
You can't teach dump and chase strategy to 10 yr old kids who can't skate, stick handle or shoot. I feel like telling this to my son's coach, but I like the fact that the players are not improving. My son's the goalie. He's getting more shots every game.
The dressing room benches is for the players, not the parents. How many times have I seen a kid look around the dressing room for an open spot to dress while a half dozen parents took up bench spots.
Don't yell at players on the opposing team when they are on the ice. Don't ever yell at the players on the opposing team as they leave the ice. I couldn't believe a parent did this and it was the parent rep, the one person who should know better.
Always put a bag of extra equipment in the car. Every other game or practice at least one kid forgets something. My son's old equipment has been used by almost every single one of his teammates.
Don't scream at your child in front of other kids and parents. You look like an abusive parent. "Look like" and "are", maybe interchangeable. My son once turned to me and said "Did you hear how her mom yelled at her." Not exact words.