I was thinking about relatives long-dead, and a strange loyalty in not doing things that would have upset them. As I was attempting to quickly explain this background to someone else, in order to make another point, I discovered that there are some people who can be summarised very easily, and others who can't. I wondered whether there was some trend to this: male/female; good/evil; generational, cultural, or physical distance. There are tendencies, but none that created an either/or in and of themselves.
Whether we can easily summarise someone is going to be idiosyncratic. You and I will look for different things. Also, single qualities may so overwhelm our judgment that other aspects may be obscured.
I don't think I'm going to be easy to sum up after I'm gone, nor will my wife. Though sometimes people can work a lot into a poetic statement. My second son was asked in 6th grade to sum himself up in a sentence. "I'm a pessimist with bad eyesight." While there is much more to him than that, the very fact that he put things that way tells you a great deal about the type of boy he was. Maybe some clever descendant will hit upon some equally telling description for me.
However, even things we believe begin to capture our essence may vanish in smoke. I have sometimes wondered - wincingly, as it bespeaks a lack of Christian virtue - whether the phrase "he didn't suffer fools gladly" would be a sort of epitaph. Eddie Izzard showed pretty quickly that such a description doesn't narrow things down too much.