Every selfish person is potentially your enemy. Giving is the opposite of acting selfishly. Divine love is the opposite of selfishness. Christianity is the only one that teaches you can be totally changed and become a person with a new nature. We are products of a corrupt culture that teaches selfishness.
All sin is selfish.
However, we are unable to do it by ourselves. We must allow Jesus Christ to change us inwardly. You can't change the fruit without changing the root. Only by receiving Jesus Christ, and letting Him change you, can you be a truly unselfish person. Pride and selfishness always go together.