I wouldn't want to be in my teens again -once was quite enough. Looking back, comparatively speaking, it wasn't all that bad.
Now - if I could do it again with what I know now - I would probably be bored out of my mind!
It's a hard time in some ways - one minute one isn't old enough to do whatever, the next minute one is too old to be acting the way one is.
The emotions (although I still have some of them at 67!) that are so out of control and one doesn't have the experience to quite know how to deal with some of the "stuff" that life deals out.
Although I would really like to have that body again.