Personally, I was ridiculously vulnerable to influence by social groups between the ages of 16 and 25. So much so, that I impulsively joined the Mormon church and threw two years away trying to convert other people to Mormonism. I also wrote an anti-Microsoft rant in a newspaper editorial, since I was so caught up in the Free Software hysteria of the time.
Fast forward 8 years, and I'm ashamed to have the name "Brigham Young" on my resume, and I work at Microsoft -- hoping nobody ever runs across the misguided crap I wrote about my employer in that local newspaper.
Several of my colleagues wish some public things wouldn't show up in Google searches for idiotic things they did because of societal pressure before their "adult" brains fully developed. They really are much more reasonable and responsible people now than they were then.