This question is more aimed at women than men, but men can answer too if it applies.
Have you ever noticed that many clothing styles that become fashionable/trendy are downright hideous, but people wear them anyway? And then they look back a few years later and go "what was I thinking..."
Haha well sometimes I like clothes that are, objectively, kind of weird looking (and yes, some may say downright hideous), but I ALWAYS like what I wear. If I don't like the way it looks, no matter how trendy it is, I just can't wear it, haha. Sometimes I do tend to wear things that are trendy, but only because it's something new and refreshing, or it's something I've always liked that's become more available in stores.
Hmm, no. I would never wear smt just because it's in right now (lol, leggins). Fashions and trends change all the time and also your OWN style :) If I try to look back at my elementary all-clothes-blue- phase now, I would be like "holy s**t, what is this s**t D: !?" Back then, I just thought that I like blue and blue shall all of my clothes be. This all goes hand-in-hand with music and art. :)
When I was 13 I wore trendy things because I thought they were cute at the time, but looking back at my matching velour jogging suits and ponchos, I wonder what the hell I was thinking.
A year or so ago I tried out the girlie girl look and ended up with a lot of Hollister clothes. I guess I wore them because they were trendy, but it wasn't a societal acceptance thing, it was an experimentation thing. I still have those clothes and paired with the fem-androg stuff I wear now, they don't look too bad.
I've always worn what I like... It's changed a little bit over the years. But my hair was really long back in high school, and looking back, it looked totally stupid... That's probably what I look back on and regret most, lol.