From my experience the main issue with wondering why things are, and asking other people this, is that it would require them to get involved into something on a different level than they care for. Not to mention some people feel uncomfortable being confronted with themselves, their behavior, their believes, motives and whatnot.
Much like you, I wonder why most things are the way they are. And I can't even start the count the times where I ran into arguments with people who didn't give anything any thought and just went with the flow.
Perhaps it's an aspie thing in that we want to understand things rather than just do them like everyone else. In order for me to support something I want to understand it. This can be the most mundane to the most complex things. If I have no clue why I'm doing this or what I'm getting myself into, I don't want to get involved. I will read the fine print (most of the time) and question motives why they are wording it the way they do.
That all being said, I must also add, anyone who just goes with the "they just are" will not be good friends with me. Those people are ejected out of my life fairly quick. Anyone who doesn't question everything doesn't belong in my life. However, I will say this; I don't want to be this critical thinker 24/7. Sometimes I just like to sit back and enjoy something... questioning everything all day is exhausting. If I were to question things about movies all the time for example it would look something like this; why is this frame the best possible cinematographic choice? Why does this character do this and not that? And the list goes on about these things, that would take away from something that is meant as entertainment.
Though most of the time I'm inclined to wonder and question things. Though I just have to weary not to take away of fun things that are meant for fun and not necessarily for questioning. Afterall, I would also question myself and wonder "why am I even sitting down for a movie? Couldn't I do something else? And if so, why am I not doing something else?"
On the other hand; some things are probably not worth questioning as such. I guess there's a limit of sorts what's worth wondering. In other words; there's a point where "why?" because annoying. Imagine this as a conversation with someone and you asking "Why?" after each answer he/she provides. It can go on forever, but it doesn't help understanding it all. Guess that's a fine line you should be aware of.
The main issue I personally have with this fairly critical view is that it sometimes seems a bit inefficient to get stuff done. I can question my behavior inthe weirdest situations and I'll effectively waste time thinking about it, while I actually am short on time and have things to do. I guess I could go question why I question myself here ad infinitum
I just don't think most people expect grown-ups to ask such questions (and no, that's not fair).
In that case; Why don't people expect grown ups to ask such questions? Why is that not fair?
I'm poking a bit of fun here
but I guess it felt right in place with the topic at hand here, hehe.