Shiho seems to be a quiet and reserved girl who rarely talks to anyone and doesn't smile much. In fact, the only person she lights up around at school is Ann. She lacks confidence to a significant degree, thinking her volleyball skills are her only valuable attributes, and that this is "all she had." she is an extremely stressed and traumatized teenager and  it is heavily implied that she was sexually assaulted by Kamoshida. This is the "final straw" that causes her to attempt suicide. 