Yup, nothing better than free child care nowadays
Haha this made me laugh, but you are dead right when you say "what matters is the kids are having a good time" and that personifies it. I really enjoy it to be fair, other than the time pressure, 36 hour days would help a lot! My eldest has developed a massive interest in football now and will opt for playing football with me outside or watching a match over video games, and that there makes it all so worthwhile.
RE: Giving something back to society is always worthwhile