Why Atheist?

An old friend of mine, that I hadn't spoken to for years, asked my why I became an Atheist and I wouldn't tell her.

This offended her, and she pressed me. She comes from a strong Xtian background (the main reason I allowed our contact to wain). I got the impression that she was genuinely currious, and not just trying to re-convert me.

So, why wouldn't I tell her? Because I did not want to succeed in proving my point of view. I did not want to steal her comfort from her, because her faith had seen her through some really hard times.

I hope she understands.