I preach this whenever i can in regards to social issues. Whenever one of your friends, or any person, acts in a way that you don't agree with (being rude, sleeping around etc), be patient and try to think about possible underlying causes; it's much more fruitful to engage the underlying unhappiness (carefully) than to react hastily to the immediate situation.
Unlikely that there's a single cause. One possibility is that people's value systems differ: do you like smoking? Do you like eating bacon? Do you like sunbathing? For each, there are people that disapprove, or would like you not to do this, or would even ban you from doing so (I could pick more controversial examples, but these are sufficient). Conflict clearly exists - but a way of resolution is not clear at all.
