Live fast, die Young ?

For the sake of philosophical conversation, why is it the best of us are always leaving us too soon? 

I feel like the death of a friend or loved one always hits so hard, but there's this fear that we all feel in the back of our psyche that when we realise that everyone loves a person, they're best friends with everyone, they make a group of friends complete like there's something missing and extremely unsatisfying whenever they say, "Sorry man I don't have time tonight, I'll hit you up tomorrow though, tell the guys I'll be there next time." This fear is that one day they'll die sooner than expected, with no warning.

I think you know the type of person I'm talking about. That one kid in high school who is friendly to everyone, is treated like an essential part of the class as a group, everyone enjoys their company even if they aren't exactly selfless or considerate, they just have this light they never let the harsh world make dim. They don't consciously choose to burn so bright with any expectation or notion that they'll die young, they just burn bright because that's just who they are. 

But then one little thing happens, one just ONE very unlikely, unforeseeable anomaly causes their untimely death. Maybe it's an instance or event that you'd think would just be like an egg colliding with the brick wall that is their history of glory and emotional fortitude.

I think one example would be Robin Williams, no explanation needed. And these people don't even need to be celebrities; to their friends, to the people they live amongst they might as well be famous.

Do you share this notion that the good ones are always dying too soon, that those of us who burn bright often die young? Do you think it's destiny, or is it something else?