
That happened with me with a show I saw, where the ending brought the main couple together again to start over, because they broke a curse that had been put on them. One of them didn't remember the other, but is immediately drawn to him, and the other guy asks if they can go on a date, and the one with amnesia says yes. So clearly they found each other again, and the love that kept bringing them together was real, right?
No. If you had been around the audience of that show when it ended, you would have thought the mains performed a double suicide. People were calling it the most depressing thing they ever saw, like "they don't deserve this!" and "I'm gonna drive off a bridge!" And I wish I were kidding, but I was SO confused. I kept asking if we watched the same show, but people were melting down over it.
All I can assume is that they were upset that he lost his memories, despite the fact that the memories were torturing him for hundreds of years. He gets to start over, and now they can love one another in peace. But so many people were losing their minds over it. It was so weird.

That's the thing with Interpreting things, we all have our own ways of doing things
That's also why before reading any novels iam interested in, I only focus on the good reviews not the bad ones because I want to give it a shot and read it from my perspective not others
Mangas are kind of the same thing
What others find annoying may seen okay to u and not that big of a deal

... I said that because I was agreeing with what you said, but now you're basically disagreeing with your first point as far as the ending being obviously happy. Perspective applies in this case, too, as the people who say it's a sad ending have perceived it as such.
Lol, it's fine, just kind of funny. Best of luck to you!
I was so excited for this drama after seeing the trailer, and I was told the manga has a happy ending--but now it seems like it's more of an ambiguous ending. I really, REALLY hope they don't give the show a sad ending, or I'm flying to Japan to beat whoever is responsible with a big bag of oranges.