It's been a little bit since I finished Golden Time, but let me see if I can toss some ideas back at you. [Golden Time spoilers](/s "To me, Ghost Banri was almost unbearable. Literally put the show on hold and contemplated dropping it if the show decided to use whiny ghost boy to get Linda and Banri together. Thank god it went the other way. I agree 100% that it was ultimately unnecessary. I feel like they saw that they were doing the memory-loss trope, and wanted to add something to it, to make it feel like more than just the average trope, but ended up falling flat.

For the whole Koko turn at the end, I didn't like how she decided to abandon him either, but I think there's a few things that justify her actions. I felt like Koko had the right to be selfish in that situation, and it also felt like the first time she was being truly selfish. She took just heaps of Banri's shit, like the Linda nightclub situation or the reset Linda freak outs, and found a way to blame herself or not let it affect her feelings toward Banri. Her thought process was also sound IMO. Every time Past Banri shows up, no one was even in the picture except for Linda. With no memories, or even space, for Koko, there was no way she could continue their relationship if he reverted back to his past self. The only way their relationship has a chance of continuing is if Banri can remember the memories of Koko. Knowing all this, Koko decides to break up Banri. Now, if it had ended there, then I'd say yeah, Koko didn't really need to be with Banri, she couldn't accept his reality, so it's okay if Banri chases Linda instead. But, when she tells Banri that she loves him, can't be with him because he's going to forget her and that would hurt her too much, and that if, somehow, he remembers her, she would stay with him forever, I began to understand her actions. She does a lot of things throughout the show to make it easier on Banri, while shouldering the load herself. In the situation with her breakup, even if Banri might be hurt for a few days, when his memory comes back, he'll completely forget about it, and move on. But for Koko, she has to let go of something she loves, and pray for it to come back. I believe this is also why Koko initially doesn't go to see Banri on her own, because she doesn't want to potentially cause any problems and wants to see her loved one come back to her. I really didn't like Koko at the beginning of the show, but it really does a good job of making her into a girl that's easy to root for. IMO, Banri doesn't deserve Koko, but Koko x Banri is definitely the best ship in that show. Anything's better than Mitsuo x Linda.")