At one time or another, pretty much all of us will have cohabitated with someone else—whether it was living in your childhood home with family, sharing a dorm room with a random roommate in college, living in an apartment with friends, or taking the plunge and moving in with your significant other. No matter the scenario, if you've lived with someone else, you know that it's not all smooth sailing. Fights can happen. Passive aggressive behavior like shouty sticky notes may appear. Friendships or relationships could turn sour. When you live with someone, you see how they are when they're on their A-game, and, well, when they're not.