Don't you have trouble with their beliefs?
I have no issue with people being religious. I only have issues with it if they try to force it upon others, but that's the people at fault on that one.
do you think it's normal for people to believe things that are impossible?
The existence of deities in general is not impossible. If you think it is, then you'd better change that agnostic label to "gnostic atheist". Which, btw, is not a better position than being a gnostic theist. Sure, some of the specifics of certain religions have been disproven or are logically flawed, and people often believe in those portions as well, but so long as it doesn't make them act like garbage, I don't see why I should care. You might bring up those that try to get their religion in schools, yada yada yada, what do you think I mean when I say "act like garbage"? If you want your kids indoctrinated, fine, don't force the rest of the students to go through it too.
do you knowingly have deluded people as friends
Probably, like a guy who thinks that he is the hottest thing, and he ugly. Doesn't mean I can't enjoy his antics.
That's because you are the deluded one; you are entrenched in this superiority complex that puts you above theists, but it makes you act like a jerk no theist would openly be around. And I cannot fathom how you think you deserve it, when your grammar is so bad that the periods are abandoning your diction.
, I may have deluded people as friends but they haven't informed me of any strange beliefs they have, if they do they are doing a good job of keeping it to themselves.
They probably wouldn't tell you about it, because they know you'd give them crap over it. Just like most atheists in the U.S. don't bring it up for fear of retaliation, your theist friends don't want your retaliation. Is that really fair to them, are you a good friend for making them feel shame and fear? No, you're a jerk.
Crazy ideas are not the same as crazy beliefs
The only difference is that it is implied in the crazy beliefs that someone thinks it is true, where that implication doesn't exist for the crazy ideas. I fully admit that I find some of the beliefs of people on here to be... quirky, but that doesn't entitle me to treat them horribly.
, being ill informed is quite common but deliberately believing in the impossible is unforgivable, there is no excuse for being deliberately ignorant.
Well, there are situations that I can think of in which being deliberately ignorant would be the smart choice, but none of this is relevant to treating people with respect. Give people the respect they are do for a debate, or leave.