My problem with Christians? Most of the time I have a problem when they try to broadcast their beliefs as a reasonable alternative to Scientific advances, and then when I point out the fact that it isn't they tend to bitch at me.
So really, I wouldn't have any problems if they just didn't talk, or when they did they realized that they have no ground to stand on, so they really should stay out of the way of anybody who knows what they're talking about.
I don't hate Christians or anything ( I wish people wouldn't be Christian, and a host of other things, but meh), I just don't take kindly to people trying to pretend that their beliefs are reasonable when they really aren't. :(