I personally think the ending was great. I mean, I understand that a lot of people wanted MC to end up with sensei; however, I think the decision she made was the best one she could at the moment. I read how some people call her weak-willed and easy to fall out of love. It wasn't exactly the case. Remember guys, she is just 16. She got her heart broken by the person she loves with all her heart and got told that he didn't love her. Given she really believed him, how would you guys think and feel if you were in her place? Also, think about Mamura who was always there for her every single time she needs someone to be by her side. I think Mamura deserves her the best. And the things he's ready to do (or more accurately, sacrifice for her sake.) I really loved it when he told Uncle Yuki that he would do anything to make sure she's happy and won't cry again. Plus, he's really respectful towards her and even let her go sensei in the end, even though there was a chance she won't be coming back. I think that's best boi right there. As for sensei, I do feel bad for him. It was the timing. It just wasn't meant to be. But to be honest, I think it was also the bad choices he made. He didn't have to hurt her that bad. If you truly want to be with someone, there are many ways to do it. So what if you have to wait a few years? You can always just ask her if she's also willing to wait for you? And sensei was also pretty indecisive and fickle for most of the story. It was that part where he lost to Mamura. Mamura knew exactly what he wanted and fought for it bravely.