To my readers, if you have experienced the displeasure of having a roommate you did not get along with, then you can definitely relate to my woes. As someone who lived for a year with an individual whose priorities were completely messed up, and whose attitude needed urgent fixing, I learned a lot about what to do and not to do in a co-ed living situation.
As roommates, you would expect the other to respect boundaries, but when there's a clear lack of respect on that behalf, things can become a little messy.
For those seeking a roommate, make sure you completely test out their personality in several scenarios with you, because casual hang-outs where you both get along do not constitute a decent pair for living together. Furthermore, try to ask others who know that individual if they are good at upkeep with their own things or at least obtain the perspective to recognize if your personalities are ones that mix well.
In my case, I didn't do many checkups because I was desperate to find someone to live with so I could lease an apartment near school and we ended up being like oil and water. I am very independent, he isn't. I like to have a lot of private time to myself where I listen to music or do wherever, and he constantly wants to be next to you doing the same thing — it wasn't working, clearly, but I was trapped in a year-long lease with him.
If you're going to be living together, make sure to notify before you're having people over... and with TIME. You can't spring it up on the other person 10 minutes before arriving. That isn't fair and appropriate to the other person needing to put up with company they may not have wanted.
Near the end of my lease, my roommate had brought someone over giving me five minutes to prepare, and then he proceeded to say they were staying over — something I was NOT happy to hear. Please don't be this kind of person. Have the decency to give notice with appropriate time and consideration for the other person.
Roommates should also keep their life in order. What I mean by this is, if you have to pay the rent by a certain time, make sure you do it. You don't want to be the one who has to constantly be reminded by the other to pay their rent or other bills. You are not a child, and if your roommates have to resort to treating you like one because you aren't fulfilling your responsibilities, then you do not deserve to room with other people.
Pro-tip: learn to be a somewhat functional and responsible adult. Please and thank you. It will come in handy considering you won't be that guy.
I could go on and on about all the things my roommate did wrong, but I think everyone gets the point. What I'm getting at here is that one has to be prepared to handle living with someone else. There are those who are great at dealing with people in a living situation, and others who cannot.
Make sure you understand what kind of person you are before determining if you can even have another roommate. I dealt for a year with someone I grew to heavily dislike and was forced to tolerate, but you don't have to, if you take precautions. If you're living like this already: don't worry, karma's got your back.