Every atheist and agnostic has been asked the following question in one form or another: if you don't believe in god how can you have any moral?
But the fact that they can't even imagine morality and good deeds without the fear of a vengeful god should be clue enough of what they believe deep down.
Sure that's true for SOME christians. Just as it's true that SOME atheist don't give a good goddamn about their fellow human beings. My point was that you were making blanket statements about christian charity that are just as ignorant as a christian who can't imaging morality without hell.
So do some christians do charity because they fear hell (either consciously or subconsciously)? Yes. But not all.
Next time, you should ask them why they do what they do and think about the meanings behind their answers.
I have, and I have found exceptions to what you claim. I'd also like to point out that many atheists/agnostics have taken umbrage on this very site when theists think they know better the underlying reasons for why they do things. (see the Are We Prisoners of Sin thread)
Just as there are christians that do not take the bible literally and do accept science, including evolution, there are christians who really do want to make their communities better places, because they want to be christ-like, not because they fear damnation.
We have many intuitions in our life and the point is that many of these intuitions are wrong. The question is, are we going to test those intuitions?
-Dan Ariely