Peer pressure is real, it often functions at subconscious levels, and it can really mess you up regardless of whether you're 14 or 64. You have to be very strong intellectually and spiritually to resist it. If you missed out on having parents who would school you on the importance of being yourself and having higher authorities to answer to than your fellow mortals, it's even harder to defeat or even mitigate its effects. You have to be yourself in this world, but sometimes it's hard to figure out who you really are if you don't get away from the omnipresent roar of the crowd now and again.
*You should go read this post, BTW. RTWT.