One thing I've noticed since I first moved into my new home here in Toronto is that I've yet to hear that phrase even once. Every time I've asked for an explanation for something, I've been given one, and have had no encounter with that dismissive, domineering catch-22.
Back in Ocean City, that was one thing I always heard. If anyone else has been in my position (I'd be hard-pressed to find one who hasn't), then you'd probably agree with me that not only is it incredibly disrespectful, but it's obviously as I said above: a method by which any person of authority can dismiss someone who questions them without answering the question, without even regarding that the question was posed, and yet still not look any weaker in doing so (at least to the unthinking masses -- I'm sure some people recognize it as a sign of weakness).
It made me feel like I had less value; that I didn't even have enough to deserve an explanation for something that I was questioning. I'll admit, sometimes I just asked "why" out of frustration or laziness, but I don't think I was ever that kind of child. All the way up until I was 19 (how old I was when I left Ocean City) I was very active, very ambitious, and typically wouldn't just ask questions with no particular reason. If I questioned something an authority did (specifically here I'm talking about my mom), I usually had good reason. Perhaps I noticed a contradiction, or just generally something that struck me as being illogical. Yet, I can still hear that phrase echoing in the canals of my ears. "Because I said so".
Now, I've yet to hear it once. I noticed it at one point, and decided to test it out. My uncle asked me to take out the trash (garbage day is Thursday in our part of District 3), and I just asked him "why?"
"You're probably the only one in this house that doesn't gag at the smell. Besides, don't you usually do it, or am I thinking of your sister again?"
No, he was right, I always do it, and it doesn't make me gag.
I guess the point of all of this is to say that it feels nice to be valued, and not dismissed.
And I hope that if I have kids one day, I'll make sure to give them explanations. There are ways to establish your authority as a parent (and it's necessary, otherwise you're going to end up with too much of an autonomous child), but my belief is that dismissing the inquiries of your children as being not worth answering is not the way to do it. It leaves children angry, confused, and demoralized.