Sudden transition are suspicious and cation should be applied when switching world views. It does seem like you are jumping to conclusions in your guess: "Whatever your conscious thoughts, if you had a sudden transition I'm guessing that was your subconsious mind thinking something like "Yes, this looks like a good social group to join." This is a very narrow guess which you have not backed up with evidence. I also can not find supporting evidence in my own observations and/or reading. While it is a possibility it still seems likely to be an over simplification.
Knowing that a previous belief system has been falsified(by some of it's foundation being disproven or thrown into doubt) it is perfectly fine to tentatively apply a new system of beliefs to experimental verify there correctness.
To break up the awkward silence at the start of a recent Overcoming Bias meetup, I asked everyone present to tell their rationalist origin story - a key event or fact that played a role in their first beginning to aspire to rationality. This worked surprisingly well (and I would recommend it for future meetups).
I think I've already told enough of my own origin story on Overcoming Bias: how I was digging in my parents' yard as a kid and found a tarnished silver amulet inscribed with Bayes's Theorem, and how I wore it to bed that night and dreamed of a woman in white, holding an ancient leather-bound book called Judgment Under Uncertainty: Heuristics and Biases (eds. D. Kahneman, P. Slovic, and A. Tversky, 1982)... but there's no need to go into that again.
So, seriously... how did you originally go down that road?
Added: For some odd reason, many of the commenters here seem to have had a single experience in common - namely, at some point, encountering Overcoming Bias... But I'm especially interested in what it takes to get the transition started - crossing the first divide. This would be very valuable knowledge if it can be generalized. If that did happen at OB, please try to specify what was the crucial "Aha!" insight (down to the specific post if possible).