I can second this. Same story, been thumbing it for 25 years or so. I've also used it through some fairly painful ligament injury ('gamekeeper's thumb'), and if anything I think it helped with the recovery.

I remember someone telling me 20ish years ago that, as opposable thumbers, we have more nerves/muscles dedicated to each thumb than we do for the other 4 fingers combined. Not sure how true that is, but it stuck with me.