I believe that Paul was saying to beware of being around the things of the world and not to become entangled with sin again. Jesus loves the sinner, but He hates the sin. When we become born again and accept Jesus in our lives, there has to be a change. We do not ignore the friends we had before we got saved, but we do forsake getting involved in the things we used to do, the things we allow to influence our lives.
When our desires change, people will notice that we no longer want to do the things we used to do with them. Make sure that they also know that we care for them. If we allow the love of Jesus to flow out from us to others, they will see that we have changed and will want what we have. Dare to be different.