People are insufficiently conscious of their visibility. Last night, in the dark and rain, a jogger came running full speed to cross a crosswalk from a dark wooded area between buildings who was completely wearing black. I would have hit her if it weren't for the two inches of white socks that extended above her black sneakers which allowed me to slam the brakes just a moment before.
I know it can be hard to introspect about your own visibility. My partner has pointed out to me how to be better visible when I go out on my bike. More people should think about it.
Some years ago in the Netherlands, I was cycling home through a pitch black cycling path covered by trees (so not even moonlight) with my very decent bike light illuminating the path ahead of me.
Before I could even process that there was another cyclist coming towards me, a dark figure zips past so closely that I feel their jacket brush my left hand. It startled me so much that I needed to stop and catch my breath. I could only imagine what would have happened if I had hit him head on with us both going 25 km/h.
I'm curious to hear how that incident was my fault.