Yeah the parents are the issue 99% of the time. I’ve coached recreational soccer where you have both extremes - the helicopter parents worried about juniors delicate psyche and the parents of the next Ronaldo wondering why these other kids are out there at all. One year the only other parent willing to help me was a varsity assistant football coach whose only goal was to turn his son into a man... this was an under 8 rec league.
Coached my son in Pop Warner from age 5 to age 12. Again, you get parents who want to introduce their kid to sports at 12 by putting them on a tackle football team. You be amazed at how hard an 12 year old that has been playing 5 years can hit. These kids and their parents were too. Meanwhile I had a mother (who FYI was a former college track athlete, as was her husband) tell me I was “killing her sons spirit” by not playing him at running back more, even though he was terrified of contact and would run 25 yards sideline to sideline before bet losing 5.
All that said, wanting to be a positive influence in kids lives is awesome, and generally the kids are awesome too. I have kids I don’t recognize (because it’s been 10+ years since I coached them) come up to me and say “hey coach!” I always told the parents at the start of a season that my goal was for the kids to enjoy (if not love) the sport more at the end of the season than they did at the beginning.
Again, I always say manage the parents expectations and make sure they know what to expect from you and what you expect from them and that will eliminate many unpleasant “surprises “.