Theists: What is the most compelling argument you have heard for Atheism?

[Whateverist]

The best reason for atheism is the refusal to take on faith unsupported claims which are farfetched and/or absurd on the face of it.  One does not argue their way to atheism, one merely refrains from embracing theism and other crazy sounding beliefs without good reason.

People have different opinions about what is far-fetched or absurd do they not? I find the Dawkins's notion that we are "biological robots in a meaningless universe" and Dennett/Churchland's assertions about consciousness being an illusion - both of those - absurd. I also find the notion that facts about nature can supply any kind of moral values far-fetched. And those are just the start of a whole host of conclusions that I see as ridiculous responses to the human condition. The idea of an intelligent self-sustaining ground of being seems far less implausible to me.

Apparently they/we do.  The difference I see is that the things you find far fetched are the assumption that there are natural causes for observed and/or inferred phenomena, even though we've had lots of experience historically with moving from a position of not or mis- understanding phenomena to seeing better and better how natural systems fit together.  The thing I find far fetched is the inference of an unnatural agent with powers surpassing anything ever observed based on no observation whatsoever - well, unless you count attributions to it to explain away our ignorance.  I'm just way more comfortable acknowledging our ignorance which is an ordinary and common phenomenon.