Agree to Disagree?

How do you love someone with whom you deeply disagree? I'm not not talking about disagreeing about small things, or "cultural" things but vital, important, key ideas/motivations/beliefs? I'd rather avoid the person. Or at least avoid the subject. But that isn't always possible. So when you have friends in common, when you rub shoulders regularly, how do you not only treat them well, but still "like" them? It is far easier to despise someone you feel is wrong and misguided, whom you believe is leading others astray (even with good intentions), than to want good things for them.