
Wait.
Isn't this her first relationship? Isn't sempai her first boyfriend? She still doesn't know how to be with someone, maybe.
Yes, she's doing something wrong, but I don't think she deserve alla this hate now.

seriously! you can't know how to treat a bf if you've never been in a relationship. all of those pretty words go out the window when you're in those situations when your partner feels neglected. & honestly no one showed any interest in her romantically until recently, so how is she supposed to know how to act in a romantic relationship?

It's still not okay. She decided to go to the Con (With the "I had a blackout" excuse) over the anniversary of Mutsumi's grandpa's death, someone that was important to him. If it were realistic, she could have asked Mutsumi if they could go the next day because of the Mirage Saga Con, but no. Then she blatantly forgets that Mutsumi wants to go to a movie over Mirage Saga. Again, not okay. She doesn't even bring it up with him in the slightest on either occasions. Even when she's told to not go, the author makes her a zombie over the words "Mirage Saga". I'm not going to justify that crap. If you're going to go to a Con over what you're boyfriend wants to do, tell him instead of forgetting immediately or becoming a zombie. Also, you even stated you wouldn't do that same thing that Serinuma just did. I can understand her actions to an extent (Wanting to go somewhere else, not where her bf wants to go), but then she just stands him up.
It's fine if she has an obsession over Mirage Saga, but if I knew someone with that much of an obsession like hers I would put her into therapy or ban all of her games. Her mind is completely full of Mirage Saga and that's not okay. Would you understand if she had kids? If she just flies out of the house with the words "Mirage Saga" in her head, leaving her kids alone and neglected? This can be comparable to Mutsumi. He's being left all alone and neglected of Serinuma's love over the words "Mirage Saga".

you're not being realistic. to a person who has no romantic experience and her whole life was her hobbies---you can't expect her to change after one or two chapters. no one said it's okay, but a lot of people have to learn how to live their life with another person. not everyone starts out as considerate as you are. this is a lesson for kae & all readers who behave and thick like her. charas can be flawed, just like everyday ppl & they have to work through things that they don't know.

That's the problem. She doesn't need to be a perfect character, but she shouldn't just go and forget Mutsumi's request immediately after he asks them just because of "Mirage Saga". I can understand the theater situation because she thinks that Mutsumi will be okay with it, her going to a Con with someone else (and a guy for that matter). However, she could have told him that she wanted to go somewhere else instead of immediately forgetting. Hell, she didn't forget because her friends bombarded her with her selfish thinking. It's relatable to an extent, but she could have told Mutsumi to cancel.
The one I'm really annoyed at though is the cemetery. You think that it's realistic to have a blackout in a Con while you're standing up someone else? No, but it's realistic to forget, then apologize. She just says that she doesn't remember what happened after she was invited to the Con. With the theater, Mustumi would have been fine with being told to cancel because they could do it another time in the future. It's not of that much importance. They would go to the cemetery another day, but how would you feel if you wanted your date to come with you to see an important loved one on an anniversary of their death, only to stand you up and say that they didn't know where they're doing? That's kind of a douche thing to do, so it's understandable that the audience is angry at Kae on that one. How does someone black out at a con, but never blackout at other cons? Or anywhere else? To Mutsumi, that could so pretty convenient.
OH SHIT.