What conversion stories have in common

I've heard or read quite a few stories of religious people who have lost their faith. I'm also aware of (fewer) stories of atheists becoming religious. And though these could not be regarded as anything like a representative sample, they do appear to have certain common characteristics.

Religious people who give up their faith seem to do so because of nagging doubts that increase to the point when they can no longer, in all honesty, continue to lie to themselves.

The non-believers who become religious appear to do so as a result of some emotional experience. Not because of reason, or persuasion, but because of some susceptibility to an emotional appeal.

My reaction to the first set — the believers who lose their belief — is, "What took you so long?"

My reaction to the second — people who convert from non-belief to belief — is plain bewilderment. How can they be suddenly convinced of the existence of God when there is, as far as I can see, no justification for such a belief? (I appreciate that this could be my failing rather than theirs.)

I've examined and refuted to my own satisfaction all the "arguments for the existence of God" I've encountered (and I'm willing to consider others), but it's clear that while these arguments aren't convincing to me, neither are they the cause of belief in converts. Believers of all stripes may attempt to bolster their faith "after the fact" with these arguments, but I don't think the arguments play any part in conversion from non-belief in a deity to belief in a deity.

Religious converts have rarely become believers as a result of rational argument, so it's no surprise that only rarely can they be subsequently reasoned out of their faith.