I am not an atheist, I am an agnostic - which means I do not know, and I do not believe anyone else knows the answers to the big questions. People take different routes in the face of this "not-knowing": you can embrace it as part of the human condition and try and lead a good life (my position); or you can search for answers via science (I am not a scientist, but listen to their evidence); or you can search for supernatural answers. I shy well away from the latter as we know where that has led: wars, repression, intolerance, fundamentalism, evangelism, interference with other cultures etc.
Because religion deals in fundamentals it is hard for it not to drift towards fundamentalism, which I define as a desire to make others believe as you do - e.g. by adding a bible to parcel of gifts.
As I have said before on another thread, I have many close friends who are Christians (and 3 of them are vicars) but we feel no "animosity" and neither they nor I seek to influence the others' beliefs, which is as it should be.