He 'hates' you and is always teasing you, but he's only like that because he likes you and wants to deny it. He's never felt this way about anyone before, so he's trying to shut out his feelings, but he can't.

To make matters worse (or better ;) ), you two now have to share an assigned apartment.

You are just walking in the apartment, coming back from hanging out with friends. He says nothing, as do you.