Genre fiction seems to have rediscovered a powerful piece of storytelling: the ending.

The most obvious example of that is "Avengers: Endgame," which has been described all over the media by Marvel Cinematic Universe mastermind Kevin Feige as a finale of what began with "Iron Man" in 2008. That is to say, the overarching story that Marvel has told through three "phases," constituting 22 movies, has come to an end with "Endgame."

And, while many fans will grieve for those Marvel characters whose story is over, it's not a bad thing at all. If these stories went on forever, as they do in the comics, one by one the actors would have to be subbed out anyway as they aged out of the roles.

As Mr. Spock once said, "the only constant in the universe is change."

So why not control that change? Why not make it count? Why not tell a powerful story — one with a beginning, a middle and an end? Comics, of course, have always taken the opposite course. There's no permanent change there; Clark Kent is still a mild-mannered reporter after 81 years, and Peter Parker is still in his 20s after debuting as a high school student in 1962. Even mortality is meaningless in comics, as what fans laughingly call "the revolving door of death" routinely brings the dead back to life with boring predictability.

For example, almost all of the X-Men have died and come back from the grave at least once. Now, that's not to say that comics are static. Stan Lee proved that with an event back in 1965 that shocked a fandom accustomed to superteams that grudgingly changed their lineups, if at all. But Lee, tired of keeping track of all the Avengers in their solo books, basically dumped all the big names from "Avengers." In a story titled "The Old Order Changeth," Lee dropped Iron Man, Thor, Giant-Man and Wasp from the Avengers roster. Only Captain America was left, leading a team of newly accepted ex-supervillains named Hawkeye, Quicksilver and the Scarlet Witch. Avengers membership has continued to be a revolving door.

That's because comics writers can't really institute lasting change with corporate trademarks. They can only provide, as Lee himself said, "the illusion of change." Sure, shake things up. But the Reset Button is never very far away.

What if it isn't? Well, it's very possible that might make the story you're enjoying that much better. Sure, it hurts when a character you love dies — and is really dead for good. But it also makes you treasure the time you spent with them, and love the story all the more.

Nobody understands this better than George R.R. Martin, who is notorious for killing off anybody in "Game of Thrones" that is the least bit lovable. And, while we have all complained about it, isn't that more like life? Haven't we thrilled all the more to the characters we have left?

I think all of us are going to remember "Endgame," and the last episodes of "Game of Thrones," vividly. Partly because they will hurt. But also because their finality will make them memorable. And pain, like death, is part of life. We should embrace that in our fiction, because it just makes the story better.