I think we need a new category of "helmet saved my life" stories. Where the helmet saved your life by staying at home and not being worn.
Some years ago I was cycling along Glen Affric to a hut where I was due to spend the weekend. Being some years ago it was before Serious Lights were widely or easily available, and since I was only set up for urban night time riding I had rather pathetic lights which I turned off as not helping (the front beam would illuminate a few wee rocks in front of me that I got in to more trouble trying to avoid than just letting big knobblies roll over them), but despite being late at night it was midsummer so I could sort of see where I was going by the contrast between the pale path and the dark heather. On one part of the trip there was quite a descent so I started going faster, which meant looking further ahead in to the gloom, but there was a problem: I had quite a big rucksack on, and the raised top pocket against my helmet meant I couldn't raise my head far enough. I decided the accident prevention possibilities of being able to see slightly
less vaguely where I was going were greater than wearing a helmet, so I reluctantly braked to a stop and took it off, and then set off again. Almost immediately I came upon a gate across the track high enough to prevent deer jumping it that had I not stopped to remove the helmet I'd have hit at some speed as it was invisible until I was practically on top of it.
So stopping to take my helmet off saved... well, not necessarily my life, but it would not
have been any fun for all sorts of bits of my body.
(Any suggestion that I would have been better off with decent lights or just proceeding slowly when I couldn't really see what was in front of me would, of course, entirely miss the importance of stopping to take a helmet off being the really fundamental safety point)
Often seen riding a bike around Dundee...