I'm just curious....

While I remember, I also got used to wearing one in bunch races (where it's compulsory), and there was a sort of passive peer pressure involved - I'd go out on training rides with groups of roadies, and after a few times of being the only one without a helmet, got sick of sticking out like even more of a sore thumb than usual. I think a similar thing has happened with smoking - although legislation was the catalyst, there's a cultural shift, and people feel the urge to belong to some extent.

And I also always wore one off-road and on the track.