oh yes, I can relate!
Hubby has 8 nieces and nephews, ranging in age from 17 to 5. Bro's kids are mostly quiet, self-sufficient, intellectual sorts and interact well with adults. They have been a lot of fun to be around. The 17 yr old is just now reaching the rebellious stage, however and is mostly reacting to limits - and his mom. He has 15 yr old and 12 yr old sisters. The kids have been home schooled; the oldest is now in a private prep school.
SIL's got 4 boys; their personalities are all quite different and they are good boys. But they ARE boys and like a pack of puppies are in constant motion - and the effort to contain their "commotion" is constant.
When I was actively parenting, I guess my philosophy was closer to the bro's and my kids were more like that. Ex #2 had 2 boys, and for the duration of our blended family, there were times when the testosterone levels in the environment shot through the roof and I went through what SIL does 24/7. I tried to channel all that energy into physical activity - sports - but even that was exhausting.
So, even though I think I'm fairly tolerant of differences in kids and parenting styles... the reality different. I like to think I'm an expert and I sure know what bugs me! Or what I can see in any given interaction, even. But, the fact is I don't know what that kind of parenting looks and feels like. It's a miracle that I did it as well as I did - and it sure wasn't perfect!!! Hubby's old school and while he can be the biggest kid of all... there are just certain things that today's kids do, are, and take for granted that just gets under skin and reads as blatant disrespect to him. And he's a nervous person around kids - except his grandson. Don't ask me what's different!! LOL!!
The one thing I catch myself doing - too much - is applying all the things I've worked through and learned about my own childhood experiences to all these different kinds of child - parent/adult interactions. These new situations are very different, especially in one respect - the parents are not emotionally abusive. So I realize that while my buttons are getting pushed sometimes (or hubby's) that what I'm responding to is nowhere near that kind of situation. I am hypersensitive, in other words. And I remind myself that normal parenting includes a kind of balance - between "Rules" and being allowed to ditch some of the rules for "fun". And that in healthy parenting situations, sometimes we do want to let the "balance of power" shift from parent to child... and back again. That's how kids learn to be independent and to separate their identities from dear old mom & dad. It's their "practice". And it's also building that relationship of trust between the two. (Something I know I didn't get to experience as a child.) Parenting just isn't an exact science and even if one gets a good "system" going with one child it doesn't necessarily apply to the next.
So even if I'm uncomfortable sometimes, with others' parenting techniques or styles I find ways to cope and allow them their space. I often learn something from it. I do look for my own opportunities to interact with the kids from my experience, speak up about my own limits or rules, and gently enforce them, even if I have to put on my aggressive self with the boys sometimes, to get their attention! I think it'll be good for you and your son to have this different experience - even if you have to retain "what works" with your son most of the time and that is different your friend's parenting style. Since for me, parenting is essentially a relationship between two people, I don't see a parent so much as "authority", in charge, infallible, etc. Sure, ya gotta be sometimes!

But it's the other stuff - the stuff of the relationship: caring, feelings, trust, fun - that is what "grows" kids into flexible, whole adults. It's the fertilizer!
