In my early 20s, I was working as a laborer on a construction site when I heard a story about a worker who jumped into a trench without appropriate protection. He was suffocated and crushed within minutes. I was also told about another worker who was seriously injured when a jury-rigged clevis broke away from a crane cab and he plummeted to the surface below.
Not many people walk around throughout their day with a risk assessment in hand, unless of course it’s the one in their phone. We should, however, always have an informal risk assessment tool in our mind that allows us to perform at least a cursory assessment until we can dig deeper or in a more formal way.