I am the youngest in my family and am very very close to my parents as well as my brother and his family, I tell them just about everything (meaning everything I choose to share with them). We are a tight family, with our problems of course but we are still very close. They don't ask about personal stuff, I choose to share it. Mom may ask "are you guys doing ok?" and will leave everything else alone. Those things I consider "healthy" boundaries, as in I share what I want and she doesn't dig for more than what I am willing to share.
My husband is also the youngest in his family and is not very close to his parents anymore, he is close to his brothers but no so much his sister. Family dynamics are different than my families (not that they are wrong, just different) and with those different dynamics, Alex chooses to share very little with his family about our lives and about our choices. This is his choice and I respect it because we come from different backgrounds. The thing that defines unhealthy boundaries in my opinion is them asking things like "paying you bills on time? or why don't you pay this? or that? or why didn't you come see us when Corrine was out of town?" I define those questions as unhealthy because first and foremost our financial status is not their business
Our boundaries are very different between our parents because we would share anything with my family and choose to be conservative with what we share with his. Our boundaries are different because everyone is different. I could not have the same conversations I have with my parents with anyone else because the boundaries to someone else would be different.
I like boundaries they make it so I don't have to share more than I would like because somethings are just not anyone else's business and I enjoy the fact that I don't have to explain any more than "I prefer not to discuss this with you" or "that's not really any concern of yours" or the blunt "excuse me, that's none of your business". I choose to try to be nice to everyone... it doesn't always work... seems as though I roll my eyes when I believe someone is trying to turn the situation in their favor and I have no patience for that. So I will try to not roll my eyes and just smile and nod from now on and get on with my boundaries that I so dearly love!