Let's re-word your question, shall we?
Adragonists (asserting that there is no Dragon), wouldn't it be more sensible if you identified as agdragonics?
Many people refer to adragonists as 'non-believers' in dragons, but of course adragonists are strong believers in the sense that they completely denied the existence of any form of dragon. Is there really any rational basis for asserting that there is no Dragon when there is absolutely no way you could present empirical evidence to support such a claim? Maybe it would be more intellectually sound to just say that you have seen no evidence (partly because you feel you have had no personal experience with the mythological....which is a shame, I shall pray to Zeus for you), so therefore highly doubt that Dragon or a number of Dragons exist at all. So rather than arrogantly asserting that there isn't any possibility that Dragon could exist, you could just say that you highly doubt it because these things are unknowable? Then you could edit your religious views (on facebook) from 'adragonist' to 'agdragonist'?
Kinda silly, huh? I mean, everyone knows that dragons don't exist, right? Especially the 50-foot-tall fire-breathing ones told about in stories of old. Right? Naturally if a Godzilla went rampaging through New York tomorrow or Tiamat rained fire down upon Istanbul, we'd have to change our beliefs in the light of clear evidence of their existence. And yet...do you seriously think that there is ANY possibility of that happening? Really? Do you think it worthwhile that we construct elaborate temples to the worship of Tiamat, just in case he turns out to be real? Would it be productive to discuss the possible existence of Godzilla's nemesis Mothra, on the assumption that Godzilla is real? Really?
You see, there are quite literally an infinite number of things, imaginable and unimaginable, which potentially _could_ exist, except for the fact that there is no evidence whatsoever to support their existence, no reason to suspect that they exist, and in some cases it would be logically impossible for them to exist. Any god you can conceive of is no different, and no more worthy of consideration than 50-foot-tall fire-breathing dragons or, for that matter, 50-foot-tall fire-breathing leprechauns.
So until the day comes when someone can present clear, irrefutable, verifiable proof of the existence of a god or gods or Dragon or dragons, I see nothing wrong with living as if such entities do not exist. If such a day were to come then of course I would change my beliefs, but I see no reason or indication that any such evidence ever will be produced. Ever.
Have you read about Russell's Celestial Teapot? Bertrand Russell also answered your question, perhaps more elegantly than I, over half a century ago: https://secure.wikimedia.org/wikipedia/en/wiki/Russell%27s_teapot
Oh, and there have been those who have made compelling arguments that there IS proof for the non-existence of at least some gods, such as the Abrahamic one: http://www.amazon.com/God-Failed-Hypothesis-Science-Shows/dp/1591026520/ref=sr_1_1