If you haven't played Kancolle, there are some ship girls like Chiyoda here who will constantly talk to their sister ships, whether or not you actually have those ships. It can be a little weird.

Yeah, sometimes Ooi creeped me out

Seeing that her sister was not yet on the base Chiyoda resorted to creating at imaginary version of her sister to keep her company... needles to say this has not had a profound effect on her mental well being.