Emotions
Tsukimori Len believes that emotions are troublesome.
Expressing them takes a whole lot of effort, is what he thinks, and there is no need to go that far just to please others. He thinks that people show emotion and laughter and smiles just for each other's benefit. So he doesn't, because there isn't anyone (he thinks) who comes to mind when he asks himself who he would like to please. Saotome-sensei, perhaps.
One might say that he isn't concerned for anyone's well-being if it inconveniences himself.
And then, there is Hino.
He sees her try her best, and all logic flies out of the window--he finds himself enjoying once in a while, finds himself cracking through the icy exterior that he has so painstakingly built up over the years.
This doesn't bother him as much as it should, though, and it puzzles him.
And then, one day, Len wakes up with a small smile on his face, and he promptly masks it with a scowl.
Hino Kahoko, he muses, and he thinks that he may just be a little bit happy.
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haha, kinda weird. like it was written on a child's point of view, don't you think? ^-^