Having grown men physically threaten you, when you're a scrawny 15 year old because a 7-year-old girl swung and whiffed at strike three is a very strange experience. As was being reprimanded for playing a kid in left field, after I asked him where he wanted to play, and he said left field.
That said I'm sure I'm going to have a few flip out moments when I'm eventually a father myself in those situations, so.
I was never into sports growing up, so I had no idea what parents were like. Then when my son turned 5, he wanted to play hockey (he's 22 now). There was a special meeting for parents that we thought was mandatory, but it turned out to be a "parent awareness" seminar that basically talked about what not to do as a parent, both during games and after. At the class I was skeptical, thinking there is no way any parent is like this.
Then I went to the first game, and holy hell those parents were frickin crazy! One mom was the loudest of them all. She didn't shut up the whole time, yelling at her son, yelling at the ref, yelling at other parents, yelling at the opposing team... Then her son took a hit and went down and the place went silent, except for her, screaming for him to get up. When she realized the entire arena went silent except for her, she said loudly, "Oh, if he were hurt he'd be crying." The next sound we heard was the kid starting to wail. That shut her up for about 5 minutes. The team made the playoffs and I couldn't believe the parents who would be up at the glass pounding on it and yelling at their kids to do things.
It was a real eye opener, and while most parents are pretty good these days, there are still a few who take it way too seriously.
The irony of that whole hockey thing is after my divorce I ended up dating a woman who had 3 boys all in hockey. Turns out she would sit with my wife way back then and watch the kids practice, and my son ended up best friends with her son, and then mortal enemies. Their high school fight ended up on youtube with some 150k views (my son won, lol). I didn't know any of this before we started dating. When we went to games, she was one of those parents who would yell and scream at the refs and other players, lol.
I did a pinewood derby car back in about 1977. My dad was inept when it came to tools, so it was pretty much a wedge. We spray painted it but my dad was impatient for it to dry completely so he put it in the oven. Unfortunately that bubbled the paint really bad and nearly burned the house down. So he ended up staying up all night remaking the car after I went to bed. We won because he used graphite on the axels, something that wasn't common back then. I was like 6 years old, so I didn't know a lot of this until years later. I can count on one hand the number of things we did together growing up (he's my step dad and we have nothing in common), so it was pretty special doing that with him.