Agnosticism and skepticism I respect and encourage, but when it come to matters of that which is inherently beyond our understanding by its very definition, I don't think that we can have any semblance of certainty in either direction.
To be sure, ardent believers also annoy me with their unwavering faith--perhaps I simply cannot see the perspective from shoes that are not my own, even when they were once mine. I was once an arrogant believer, so convinced of the truthiness of my particular denomination. Now I want to believe and disbelieve all at once, but can do neither.
There's just no evidence to prove or disprove the notion of deity, and so the scientist in me decides to sit square in the middle, on top of a fencepost, huffing and puffing all the while about those running about in either field. Fenceposts aren't very comfortable, you should know, but they can provide spectacular views.
You see, no matter where you are, it's a matter of choice. Some people choose to believe. Some people choose to not believe. Some people choose make chancy chairs out of pillars of wood. It's a personal choice and we've got to respect each other, not scoffing at believers, not attempting to convert anyone that floats into your sphere, and not getting upset when people aren't as angsty about the whole dilemma as you are. (Doesn't mean I listen to my own advice.)
I've been reading Religion for Atheists, which is inspring this rant. Botton outlines a series of points about how religion improves communities and provides individual consolation; his objective is to illuminate how secular society can use many traditionally religion mechanisms to make itself better. He is very thoughtful and his points are enlightening, but his tone is grating because it continually emphasizes the obviousness of atheism.
So I suppose it's not atheism that annoys me, its the arrogance of presuming the position of your audience. I don't like it when people presume I'm either a Democrat or a Republican. I don't like it when people presume I believe blindly or that I am constantly critical of my church. I don't like it when people presume that I believe whatever thought they're selling me at the given moment. Part of the reason I don't like it is because the people making these assumptions don't bother to justify statements that I think are in dire need of justification.
Refining an idea within a sympathetic community is a good first step, but it is not the end. The title makes it obvious who the intended audience of Religion for Atheists is, but that's just a cop-out--the work would have been stronger if it had anticipated a wider audience.
If ideas are truly good, be they political ideas, social ideas, or ideas related to belief or the lack thereof, they can and should be expressed without relying on the crutch of targeting a sympathetic audience or presuming your audience is sympathetic.