Kyotani was known for his aggressive and loud behavior, for feeling superior to others. That's why he didn't have many friends.
He didn't really have any.
The guys on the team tolerated him, tried to talk to him. Sure, they thought he was really good at volleyball, but they didn't really want to be friends with him.
Kyotani didn't have a problem with that, after all, he didn't need friends to be successful. Or at least that's what he thought.
Every night, sitting in his room or in the shower, he wondered why he was like that. He pushed everyone away before they even tried to talk to him. He didn't know what was wrong with him. He wanted to have friends, he wanted to have a girlfriend just like other boys his age. He tried to change, but he didn't even know where to start. He felt alone in all of this, because he couldn't even tell anyone about his problems.