I had no problem with my issue believing in Santa. I never told them Santa was real, but I never pointed out specifically that he was not real. As far as I'm concerned, Santa is just one of the cultural things we lay on our winter solstice celebration of the rebirth of the sun, and it's one of the happier ones, so I'm satisfied if everybody under about 6 believes in Santa and then pretends to believe until about 10.
I like to celebrate everything. At our house at Christmas, we put up a tree, strew pine boughs here and there, play Christmas music, and hang lights on the front of the house. We be festive. What I most like to celebrate are the pagan parts: Yule log, presents, tree, lights, brandy. But we also have a crèche on the mantel, a lovely woodblock set, and a dreidel, and a Santa, and a nutcracker, maybe some garden gnomes. We also have an Indonesian magic frog with wings hanging from the bedroom ceiling to ensure no birth defects in children conceived there. (It's worked so far.)
This is from as pure an atheist as you will ever meet. I know none of this stuff is real, but it's fun to play with. A friend talked me into taking an astrology course 30 years ago, and for a couple of years I read pretty deeply in mystical lore. Lots of mystical texts say pretty much the same thing, so if the basic mystical premise (that it is possible to understand the universe by direct perception and to affect it by a power of mind; that includes meditation and prayer) is correct, then we can know quite a bit about the details.
Alas, the basic mystical premise is false. But it's still fun to play with. I don't feel threatened by it. And because I think that such things as the level of one's religiosity are biologically determined, I can't even hold it against anyone that they believe what I think is claptrap. Since my beliefs are also biologically determined, there's no real reason to believe I'm right except that it just seems so clear to me.
It's like memories. Each time you recall an event, your brain reconsolidates the memory. It writes over the previous version of the memory. And if something occurs to change your thoughts about the event, you reconsolidate it as though it were a real memory. If I ask, what color was his hat? You might or might not know (since he was not wearing a hat), but you may now "remember" that he did, and you might even remember the color. You can't tell the difference between a "real" memory and a reconsolidated one. All you have in your head is the current version.
So the fact that you have a clear memory of something is no reason to think it's true, and the fact that it seems so clear to me that there is no god doesn't mean there isn't.
Actually, calling myself a pure atheist may be misleading. There are versions of a god that I am agnostic about. I have no reason to believe them, but I have no reason to disbelieve them. These are deist versions, such as the universe being self-aware, and the movements of the galaxies being like parts of our brain or body. Sounds weird, but I guess it's conceivable.
What is not conceivable is a god who knows and cares what we individually do. That's the part I find just crazy.
But merry Christmas, happy solstice, happy Hanuka, happy Kwanzaa, happy Diwali, and anybody I missed, happy whatever you celebrate.