Earlier today, I was riding my bicycle down a trail. I went to pass another rider on the left, giving her a vocal heads-up. I was nearly past her when an oncoming rider suddenly appeared. This man was on a thin racing bike, traveling at quite a clip. I slammed on my brakes and fishtailed, but managed to regain control and fall back behind the woman. The oncoming rider then zipped past me, never braking or otherwise breaking stride. While it's true I was in the wrong, only I made any attempt to avert a head-on collision.
I notice this a lot, whether I'm riding or driving. All too often, people don't adapt for conditions on the road; they simply roll based on what they think should be happening. I get cut off by bad riding/driving all the time, and it sucks, but I still slow down and/or slide over (to the degree that I have time) when that happens. Two wrongs and all that. But I'm apparently one of the few with this instinct.