Short and sweet -
I am grateful I am no longer a teenager.
Oh sure, parts of that era were excellent - but for the most part, it was pure hell. Periods of the sort of tedium that comes from not being free to live life on one's own terms mixed with insane levels of drama, intense spasms of uncertainty, periodic episodes of sadistic bullying, and ten tons of pressure to figure out what you're going to Do With Your Life who you're Going To Be, and What It All Means.
I've earned every wrinkle and grey hair I have - and nearly all of them stem from parenting someone else through their own roller coaster ride called adolescence. It's tough being a parent of a teen! The only thing harder is being the teen.