when Floppinho was 5, two of his buddies in kindergarten started bullying one of their other friends. this appeared to continue without interference from the teacher, kids or parents to the point where it began genuinely upsetting my son- to see his friends being mean, to see his friend being treated badly, and to see no grown-ups helping. we've always told our kids this kind of behavior is NOT ok, and that if they see it or if it happens to them, the first thing they need to do is tell the perpertrators that what they're doing is wrong/not ok and to stop... with the proviso that if they do it again he'll tell the teacher what's going on.
it felt like our kid was the only one doing anything about the situation- including the teacher ("I'm not seeing any of this"- 25 kids, public school, and most of it happening during recess when she wasn't there to see) and administration. the behavior continued and we talk to the parent of the kid who's getting bullied- "we don't want to get the other kids in trouble".

... ok. even though these kids are routinely picking out your kid and making him cry. one of the bullies was our kid's best friend at the time- ok kid, but there were defeinitly times you could see the eyes roll back into his head great-white style and he'd do some above and beyond wrong/physical behavior (while horsing around walking home, push our son into the street, or throw drinking bottle at his head from only a few feet away... with no repurcussions from his own dad).
floppinho's bday was right around when this all came to a head- he chose not to invite the bullies to his party because he was worried about the other friend. I made the point of talking to the great-white's dad, who I got along with and spent a bit of time with outside of school. listen- son really likes your kid, but isn't going to invite him to the party because he's repeatedly seen him be mean to the other kid. if somebody told me that kind of thing, I'd be shocked, but want to know wtf was going on so I could deal with my own son. as such, I figured this was going to be a long conversation. guy kind of nodded, and that was literally the last time he even looked at me for the rest of the school year. wife wouldn't look at either of us either. thankfully we left that place for 1st grade.
tldr, parents can be ####### idiots, myself included. and robert deniro!