I was raised in a half-Christian household. I live in a country dominated by Christianity. Many of the cultural norms are directly Christian; some of them are rooted in Puritanism. I live in a state where "Freedom of Religion" means "Freedom to be Christian." The simple fact is that to be a part of this society is to be immersed in Christiandom whether you like it or not.
Still, I don't hate Christians. I don't think they're wrong or misguided. Most of them are pleasant people. Some of them are annoying. I used to hate Christianity. It took me a while to grow up, I think, but now I don't "hate" it, I "dislike" it. Strongly, but now I can discuss the religion and enjoy that discussion. I do hate certain parts of it, and I probably always will. It's grounded in resentment and a strong does of childhood indoctrination.
What do I dislike? The explicit belief that all of the "unsaved" will burn in hell for all eternity. Hell is for sinners, according to the Bible. It's where "bad" people go. Since Dante, at the very least, and probably farther in time, hell is equated with evil. This is the first, an one of the more offensive Christian ideals. "If you don't believe the way I do, you're going to go to hell." The other things that I find offensive is the implicit superiority. For a religion that's supposed to be full of humility and non-judgmentalism, it isn't. Christians, the saved, are assured a place in heaven where they deserve to go simply because they choose to believe it. The rest of us, the unsaved, deserve to go to hell. The implication is that Christians are better than everone else. Another thing I dislike is lack of tolerance for other belief systems. That would be the religion's intolerance, not the individuals. It's god's way or the highway to hell.
The thing that I believe most non-Christians dislike the most is the proselytzing. The constant barrage of "Jesus saves!" blithering that just never goes away. For me, personally, though, the worst is when I'm told, or I'm supposed to overhear, that I haven't chosen to re-enter the fold because I refuse to confess to my own sinful nature. Anger is a pretty destructive thing, and I've got the tongue to unleash the hell out of it. It's difficult to step back and understand that these people say these things because they've been taught that this is the correct view. Why wouldn't someone deny what they see as the truth? It's simpler to say that the denier is not ready to face the truth than to question whether or not the denier has a point. This really toasts my cookies, though. It's a slap in the face, with a particularly slimy fish. I chose to leave the fold in the first place through years of a lot of angst and study. I reached the point where I today, not through some misguided sense of insulated denial, but through a lot of critical thinking and examination. I used my intellect and my intellect and I came to the conclusion that Christianity did not make sense, considers me a lesser person because I am female, is the source of oppression for others, refuses to acknowledge reality as evinced through empirical testing, and was simply not appropriate for me. To tell me that I'm not a Christian because I don't want to face my inherent "bad" self is one of the most insulting things a person could tell me. I'd rather be called a crack whore than incapable of rational thought.
People can refuse Christianity because it isn't the truth. It happens every day. Christians, well, they obviously disagree. The problem is when there's no ability to "agree to disagree" and move on with an amicable life. What Christians call the Great Commission tells them so.
I picked Buddhism because I fully agree with it's main tenets. Even more, I agree with the spirit upon which it rests: to see reality the way it is, not the way one prefers to see it. It's not I that refuses to "see" the truth. The denial comes with the inability to accept that one can rationally turn away from Christianity.