Something that is existential carries the highest weight of importance. An easy way to describe something existential is as part of the phrase: “If I don’t , I’m going to die.” Interestingly, all people have felt like this about many things at many times, even if they didn’t put it into these words. Food, water, sleep, and sex are all frequent fillins to the sentence, but some people have elevated other things to this level of importance, for good and bad. Many parents have made the well-being of their children existential priorities, and successful business people have placed their business at this level; for some, escaping pain, worry, or sadness can take ultimate priority; drug addicts treat their high with this level of importance, among many other examples.
It turns out that no matter what you put into this slot, only one thing can go there. This is one way of identifying your prime priority.
Successful people learn how to choose what they get existential about. They master how to lock in one target. They proactively plan plausible paths to obtain their existential goals, and they lock onto them like a snapping turtle until they yield.