The story of 'the unwanted room mate' could start with two people moving in together thinking it would be a great arrangement. However, as time goes by, the unwanted roommate starts to show their true colors. They might be overly controlling about things in the apartment like the temperature or the TV channels. Or perhaps they are constantly borrowing things without asking and never returning them. This gradually builds up tension between the two roommates, and the person who didn't expect such behavior now wishes they could get rid of this unwanted roommate.
Well, 'the unwanted room mate' story could involve a situation where someone gets a roommate through an ad or a friend's recommendation. But then it turns out that the roommate has some secrets or behaviors that make the living situation difficult. For example, the unwanted roommate could be hoarding things in the shared spaces, or inviting strange people over without permission, which makes the other person feel uncomfortable and unsafe in their own home.
I'm not sure specifically which 'the unwanted room mate' story you are referring to. There could be many stories with such a title. It might be about a person who has a roommate that causes problems like being noisy, messy, or having bad habits. Maybe the roommate doesn't pay their share of the rent on time or is generally unpleasant to be around.