A youth football referee has quit in a letter to fellow parents, saying he holds them in contempt.
Avery Krut has decided to stop volunteering with the Beverly Hills American Youth Soccer Association after he became frustrated by parents' behaviour from the sidelines.
In a letter released through The Ankler website, he called them "entitled" and said the way they acted was "damaging to children".
The 57-year-old, who has been a volunteer with the American Youth Soccer Association (AYSO) for about 15 years, said in his email: "This will be my last year as your referee administrator and I will no longer be the game scheduler.
"And there's a reason, I have come to despise so many of you and I hold so many of you in contempt.
"Your behaviour on the sidelines has, for far too long, been disrespectful and you are damaging the children. You have said nasty things to and about too many referees and it must come to an end.
"I can no longer be involved with so many people who feel so entitled. People threatening to write up a referee because he was wearing a protective boot was the last straw. The behaviour on the sidelines has been despicable too often."
He concluded by saying he was "done" and called it their loss.
The organisation's board responded in an email and said: "While we respect and appreciate all of the years he has given to our region, the views stated in his e-mail are his personal opinions and do not represent the Beverly Hills Region 76 Board."
AYSO national executive director Mike Hoyer said: "He certainly wanted to go out with a bang.
"We're disappointed that someone has gotten to the point of their frustration that they don't want to continue. That's just tough."
Mr Krut told The Guardian that he did not regret the email, and said some of the emails he'd received praising him were actually from people he said were part of the problem.
He said: "The idea that parents have the right to yell at referees, what kind of message are they sending their kids?
"You're taking the fun and joy out of it because you think your kid is going to be Lionel Messi."