It's all about the reflex action on a bicycle.
I crashed today because my first action was mental rather than physical.
I was pedaling the mountain bike up a gravelly alley when there was a "thunk" and the pedals spun free.
Here's where the wrong reflex cost me. I looked down to see what happened.
In the time it took to look down and think "oh, damn, the chain has gone," I had come to a stop and was falling sideways. It was too late to get unclipped and I rolled into the gravel.
Looking back, it would have better to unclip as soon as there was a problem (the reflex) and THEN look to see what it was.
I wasn't hurt; I'd already stopped. It was less a "crash" than it was a Laugh-In tip over.
And of course, being a guy, the first thing I did was jump to my feet and look around to see if anyone saw me fall.
No one did, so I was safe.
I walked back and picked up the chain, wrapping it around the seat post for the long walk home. Three miles in mountain bike shoes. <sigh>
And before you ask, yes I had a chain tool in the tool kit. But without my glasses, there was no way I could see well enough to work on the chain on a cloudy day. And therein lies a second flaw in my preparation for bike rides: there's not much point having the tools with you if you can't see to use them.
So work on those reflexes. Unclip first, automatically. Then look around.
Look before you leap. Or crash, as the case may be.