Relationships with Non-Christians

Growing up my parents always warned us about dating non-Christians and I have always thought this was purely for the Christian's benefit. Lately though I've been thinking that it may have more of an affect on the non-christian. It seems like today every action a christian takes is critically judged by the outside world and even by other Christians. I have experienced that the more I let others know that I am a born again believer the more I am judged by others. I think of my relationships with those that aren't saved and I wonder if they are seeing Christ in me. It's tough to admit but I'm sure that there are plenty of times they are not. If I let them down, which I more than likely I will, will they judge me for it as a christian? Even if I hurt them non intentionally, it may ruin their chances of coming to Christ themselves. I think about my past relationships with non-believers and I know that I did set a good example of a christian. I hope and pray that if I hurt them or did something negative to them that they did not associate that with Christianity or God. I would hate for someone to not come to Christ because of the way that I treated them.