I have a friend at work who is the definition of a christian fundamentalist. When we work together, our conversations invariably turn to faith, and things get interesting. He's of the mindset that the bible is right, if you don't accept jesus you are going to hell, and all the other stereotypical arguments that we see a million times over. We have some good talks, but in the end, i know that nothing i say is ever going to get him so see things differently.
Circular logic, self-affirmation and "you just have to believe" are the arguments i get, even when pointing out that the faith is just a hodgepodge of other older ones put together. The best is when I do catch him on something, and he says "well, nobody is without sin. We're all sinners, but god forgives us if we..." and so on.
It's really tiring sometimes, but, hey, it helps the day go by.
On the other coin side, another fellow i work with is studying to be a pastor. He's a really good person, and he recently found out i was an atheist. His reply? "People believe what they believe and i'm not going to try and force them to think the way i do"
Long story short,people like the easy way. they like to be spoon fed what to think to take away that horrid part of life, and it gives them comfort to know that they know "the right way". When you start to chip away that comfort and actually push rational thought on them they get upset and turtle up.