The firm Mayama was about to be apart. For some intentional purpose, his boss put him into the group of people who have to leave Tokyo to another place. At the same time, Rika-san's assistant was is hospital and she hasn't been able to find a replacement. Hence, Mayama decided to leave the firm and came back to work for Rika-san, without much of asking for her permission. Yamada acknowledged about this through Nomiya (Mayama's boss) and she was really depressed after that. After that, she was proposed by four guys from the shopping arcane (they were friends since small) but she ran away. Hanamoto-sensei later on explained for her that the situation of her and Mayama was similar and in that case (loving someone who doesn't love you), people could just choose either "make some effort or give it up" and advised her to tell those guys her true feelings. After Yamada left, Hanamoto-sensei's thinking revealed that there is a third choice, but he would never speak it out. (thetvdb.com)