As an atheist, one of the major problems I have is not with Christianity, but with Christians.
It's the 'I've got something you need ...' trend in their attitude that bugs me so much.
I have absolutely no problem with anyone who wants to smooth their way in this life with a belief in another one, and that a 'saviour' is waiting for them - all cool so far.
But as a non-believer, there is a definite air of smugness in the more overt exponent of 'the message'.
However, it does all depend on which branch of 'the faith' you like to favour as the 'correct one' - as one Catholic said to another - "How many Protestants does it take to change a light bulb?" "Doesn't matter," was the reply "They all live in eternal darkness ..."
And that's before we get onto the thousands of other beliefs past and present.
Grin, and nod, they like that.
Oh, and start every answer with " And d'know ..." - they love that!