I feel that perhaps you are being too cynical. There's such a thing as an insight snapping into place and recoding a lot of old information.

And there's such a thing as force building up for a long time against resistance, and then the resistance breaking; this is not sane, per se, but it's how I would describe my own sharp transition in 2003. I certainly don't think you could describe that as joining a social group.

Actually, I'd think there would be a lot of sources for sharp mental transitions. Just having to choose locally a preference between A and B will generate sharp transitions whenever A < B swaps to B > A and that means other things have to follow.