I've had three minor offs (10-20mph) commuting around London. They act as a slight wake-up call that life isn't a video game and that consequences can get real but ultimately, each time, I've just got on the bike, rode it home, fixed it up and carried on riding.
I do however wonder if my outlook would change when (or if...) I have children. I think I would have to reassess my priorities at that point.
...Edit...
I have to say though, nothing validates my decision to ride more than passing the 100+ cars on my way to and from work each day. Biking is the only sensible option to do my commute as I see it. I'm not crawling around in a procession of cars for hours or getting shoved in to packed tube trains every day just because there are risks involved. I take those risks and still feel better off.