Discussing controversial subjects like politics and religion will do more harm than good. You're not going to convert anyone to your point of view. Instead, you'll offend people who could be your friends. Set aside your judgment for the sake of personal interest. Just because you don't share the same ideals does not mean you can't find any common ground. Stick to innocent subjects like art, music and sports. You'll find shared interests with someone whose background is much different from your own.