I was raised atheist, and it wasn't difficult at all. In fact, I only know the religion (or lack thereof) of one of my childhood friends, which I learned not because he made any statements of belief per se, but rather via his complaints about having to learn Hebrew. As for the rest of everyone I went elementary school with -- we did have occasional critiques of Santa, but it never occurred to me to extol atheism because the topic of religion never came up. When I eventually learned of the great quantities of deluded people around, I had to infer that some of the kids that had never mentioned religion probably were religious, but it didn't seem important enough for me to actually ask to determine which ones.
I don't think I grew up in any great rationalist enclave, maybe my school was just really serious about separation of church and state?
I share your experience.
Related on OB: Lying to Kids The Third Alternative
My wife and I are planning to have kids, so of course we've been going through the usual sorts of debates regarding upbringing. We wondered briefly, will we raise our children as atheists? It's kindof a cruel experiment, as folks tend to use their own experiences to guide raising children, and both of us were raised Catholic. Nonetheless, it was fairly well settled after about 5 minutes of dialogue that atheist was the way to go.
Then we had the related discussion of whether to teach our children about Santa Claus. After hours of debate, we decided we'd both have to think on the question some more. It's still been an open question for years now.
Should we teach kids that Santa Claus exists? This isn't a new question, by any means. But it's now motivated by this thread about rationalist origin stories. Note that many of the posters mark the 'rationalist awakening' as the time they realized God doesn't exist. The shock that everybody, including their parents, were wrong and/or lying to them was enough to motivate them to pursue rationality and truth.
If those same children were never taught about God, Santa Claus, and other falsehoods, would they have become rationalists, or would they have contented themselves with playing better video games? If the child never realized there's no Santa Claus, would we have a reason to say, "You're growing up and I'm proud of you"?