If someone is the complete opposite of me in their perspective on something that is very important to me – or that I think shows good or bad character – chances are I’ll dislike them. For example if someone is homophobic, loves rape jokes, and thinks the nazis were cool guys, I must say I find it pretty hard to like them.
But minor differences I just take as differences and leave it at that.
I even find myself liking a lot of people who do have very different political and moral beliefs than I do if they try to understand where I’m coming from, and can disagree respectfully. Even if they’re thinking “God this person is so wrong,” the fact that their character is good enough to keep that to themselves and instead debate it respectfully is enough to make me at least partial to them.
I never lump everyone of one group into a ‘bad people’ pile. For example, I’m generally more liberal-minded on most things (at least when it comes to social issues), but I hate when liberals regard all republicans as awful and evil, and vice versa.