When one of the authors is missing her deadline due to getting sick, Ritsu offers to head to the airport where she's at and help her finish the manuscript. Despite being told repeatedly that it's impossible, he persists and gets Takano's permission to go, and indeed, returns with the finished product.
Takano telling Yokozawa straight-up that he is in love with Ritsu and always has been, and only sees Yokozawa as a friend. Even if you feel sorry for the the latter, it's hard to admit that he didn't have it coming with how he's been treating Ritsu since day one, especially since Ritsu was dealing with many other problems at the time.
Kisa telling off one of the many people who he slept with, who doesn't seem to get that a one night stand is only a one night stand.
Which is followed later by Yukina warning the man to back off when he returned to hound Kisa again.