A former US Secretary of Defense once said (although in an entirely different context)
......there are known "knowns." There are things we know that we know. There are known unknowns. That is to say there are things that we now know we don't know. But there are also unknown unknowns. There are things we do not know we don't know.
His words were widely mocked as gibberish at the time IIRC - mainly by journalists - you know - those people whose business is words! - but I've found it to be a good philosophy to live by in my life.
It may happen that one day, right after that bing-bong, you get to know something you didn't know you didn't know....and it could possibly save your life in a sticky situation.