Faith is totally bizarre. Faith means believing in something without having any evidence to support your belief, but its definition is not really what makes it bizarre. Faith is kind of the opposite of the philosophy called science. In science you believe only what you can prove. If you can't prove it, you doubt it and instead of calling it a 'law' you call it a 'theory'. You can disprove competing theories all you like but until that special theory is proven, you know your belief in it is not absolute and understand that it shouldn't be. As far as things go, laws are best, but theories are fine too, that is until a better one comes along in which case the old theory is dropped like a hot potato.
And then there is faith. If you find evidence to support your belief it ceases being a matter of faith. Faith is by necessity vague and uncertain, though those that have it often give it more substance than any scientific law. Technically speaking, this isn't rational, but faith isn't even remotely related to rationality.
Then there is this odd duality of faith.
If you blindly put faith in your fellow man, they call you naïve.
If you blindly put faith in God, a force that none of us has ever seen, heard or felt, they call you spiritual (or pious, devout or religious -- take your pick).
The sheer illogicality of these two attributions, and the enormity of the gap between them, is what I consider bizarre. How can this be?
The absence of concrete evidence of the existence of God (or gods if you prefer) means that there is also no evidence that this 'omnipotent force' has ever let anyone down. On the other hand, I'm going to suggest that every single one of us has been let down by their fellow man at least one significant time in our lives. That's all it takes. Even if you are a positive person and believe that given the choice of right and wrong people will overwhelmingly choose right, you still recognize the danger of placing faith in the generalized other. That is more negative than the universal perception of divine powers. And there lies the source of the naïve and spiritual labels. (Actually, faith in man is sufficiently derided that you'd raise fewer eyebrows by putting faith in your pet dog.)
Even with that explanation I still find it bizarre. I suppose that makes sense as I am an extremely rational person. Faith runs counter to just about everything I understand or hold dear -- it just isn't in me. That more than anything else is probably why I find it so bizarre.