Grave of the Fireflies.

Requiem for a Dream.

Grave of the Fireflies, though I'll probably watch it again someday anyway since I'm apparently some sort masochist.

Oldboy.

One and done.

SLC Punk

More recent, The Whale is a triumphant return for Brendan Frasier that was absolutely stunning. And I can never watch it again. It's so good because it was so gut wrenching. Everyone should see it - once.

Everyone should watch and enjoy Life is Beautiful.

And then everyone should have a nice rest period to let their feelings recover before considering rewatching. Minimum a decade, no maximum.

La Haine
The Broken Circle Breakdown

The documentary Dear Zachary: A Letter to a son About His Father.

Starts out as a home project someone was putting together after his friend died so that his unborn son would know his father and it just gets worse from there. Amazing movie, would not recommend unless you need a few good cries

Probably Dragonfly. It's not a world class movie or anything. Most of it was draggy as hell. But then that ending hits, and it's worth it.

But I don't think that a second watch would have the same wow factor at the end. Knowing it's coming, and still having to slog through the first half, I don't believe I'd enjoy it.

Edit: or gone with the wind. Great movie, but it's gotten harder to ignore the flaws in the story despite the movie itself being a masterpiece. I think if I watched it again now, knowing more about the era and the bullshit that got crammed into the book that showed up in the movie, I couldn't be immersed in it.

Tusk

Incendies https://m.imdb.com/title/tt1255953/

Bicycle thief. Movie hit hard...

In the Name of the King: A Dungeon Siege Tale