Yes, I have. But I do not fully blame the people around me for attitudes, behaviors and values that I have come to adapt in order to conform to their's. I think, partly, I, too, am the one to blame. Had I been firm with my moral grounds and to what I believe is right, perhaps I wouldn't have changed much.
Ever since, I thought I was a very awkward person. I do not know how to present myself to other people or how I should behave when I'm in front of a crowd. But since I often hang out with my friends I met in college, who I think are very good at this, I eventually learned the art of socializing. However, this act also led me to learning how to smoke and drink. At first, they said, "Go ahead and try. It'll make you feel better." I didn't do well the first time but they told that I should do it regularly if I want to experience the pleasure of doing it, especially in smoking. I tried to refuse but my curiosity got the better of me. Back then, I also didn't want to get the feeling of being left out, as I'm the only person in our group who would drink fruit juices instead of beer, so I decided to try it.
Until now, I still drink and smoke sometimes. But I take comfort in knowing that whenever I feel like quitting, I can certainly do it.