No worries. You're not the only one feeling that way. People simply get happy from the happy ending. Forgetting that there was barely any connection between the main characters for it to feel satisfactory. The manga spent so much time on flashbacks that they forego any development between the main characters. Like the only interaction btw them is simply like the first time they met, the sex and when they had troubles. They barely showed anything besides sex btw the main characters and even that were so little.
Not sure why people are happy just because it's a happy ending but I feel cheated.
I totally agree with you, I felt like this was gonna be a masterpiece and I feel super cheated as well, but oh well it's over.
Time to move on to something new I guess.
I don't know what the hell I just read, felt like a rushed ending. Didn't even understand they were flashbacks, the fuck. What a bad manga.