He Was a Good Person

One way to ask yourself if you're a decent human being is to ask how many people would come at your funeral. I think that's a poor metric. When you die, people default to remembering your best parts and ignoring the worst. You're dead, after all. It wouldn't be cool if someone rants over your corpse. But despite people remembering you well, most of them still won't probably come. Quoting Alan Burnside from Nothing But the Truth(opens in new tab):

A man can live a good life, be honorable, give to charity, but in the end, the number of people who come to his funeral is generally dependent on the weather.

So "coming at your funeral" boils down to simply "remembering you well". And most people can remember you well for all sorts of reasons when you die. Naturally, they'll go back in time and visit all memories they have with you. They'll surely find something nice to hold on to.

But what about the random delivery guy or the cashier at a distant grocery store that you'll never visit again? Will they remember you well? No, they won't. They won't remember you at all. You were a tiny insignificant blip in their lives, let's not forget that. However, we're talking about a way to tell if you're a good person, not being significant. So if you can make that random person feel anything remotely similar to what other people would feel when they remember you upon your death, that's great! Your lives intersected for a very slim window of time, yet you still managed to make a difference. You should strive to invoke that feeling in everyone, every time you say your goodbyes. Who knows, maybe that could make you more than an insignificant blip.