So lots of people desire to fit in. So when they are in a group of people doing things that are wrong (even though they believe/know it is wrong) they desire so much to be accepted that they do whatever it is. If they do not have perseverance or really firm beliefs in what they think is moral they will do what is wrong. Similar to the quote 'You are what you eat' you are who you are around if you are around a whole bunch of bad you are going to be bad. So if you desire to be accepted or are in a group of people who do what you think is immoral you are likely to feel as if it is ok.
