I totally agree with some of mentioned above:
Gobin: same reason about the age difference... okay, there is a lot of ajusshi romance out there, but for me he treat her more like a guardian than a lover. It could be that her love was more because she had a reliable person than because it was a romantic love? (please dont hate me if your opinion is different). I think I could be okay with them if they changed the lead actress at some point to someone older. (but I know it is not usual in kdramas...) I love her, but she is just too young for him. I love the main lead too, but he is just too old for her. I dont know if this is also part of the story, but if it is, I didn't get it.
Hit the top: I read spoilers before, so I knew she would end up with the father, but I kept watching because I didnt want to be prejudice. But even if the "father" is like, not the real father, the person before meet his mother and whatever... he wouldn't be a least touched to know he had a son? Idk... I kinda understand but at the same time I dont. He knew his son liked the girl... but the son never had a chance anyway, she never liked him... I wish he had more romance scenes with the trainee girl because I think he deserved to be loved because he was cute lol
Drinking Solo: I liked this drama bus I hated this male lead. The younger boy was so much better. The male lead was too proud. At certain point of the drama he was supposed to get better but I think he didnt chaged much. Got on my nerves...
The K2: One of the main reasons I couldn't finish this drama... Yoona is cute but I felt something was missing. Ji Chang Wook has chemestry with everyone. I couldn't believe this one. One day I have to try watching again to prove myself that they can also be a couple.
Doctor Stranger: I am currently watching but if the main lead doesnt end up with Kang So Ra I think I will drop. Didnt like the other female lead.
Cheese In Trap: I think the ending was kind of open, but the female lead will not end up with Baek In Ho. Yeah, yeah, he is supposed to be our SLS. I just can agree with it if the other male lead fix his issued because he was seriously messed up. No problem with that, but in my point of view he needed help.