You meet a person. They are charming. They have exciting stories to tell and interesting things to say. They come up with hilarious jokes spontaneously. They don't smell. You need a place to live. They need a place to live. And so you hit on the brilliant plan of sharing a place. Three months later, you would kill them if you thought you would get a moments peace before the cops arrived. They have told you every story at least sixteen times, with every telling changing just enough to prove the story totally false. Their interesting ideas started sounding idiotic after the billionth repetition. And you have discovered humor books in their possession with all the spur of the moment jokes they tell underlined. You recognized them because at this point you could recite them in your sleep. And while they still don't smell, you do, because you no longer enter your bathroom for fear of disturbing the things growing on the floor. You give yourself sponge baths at work instead.
The problem with living in the same house with someone is that you live
in the same house with them. You don't just know what they look like in
the morning, you know what they sound like when they come. You know that
while the rest of the world finds them charming and smart, they are
secretly dull cretins. Not to mention rude. Just look at the way they
roll their eyes and fall asleep every time you start to share an
interesting thought or tell an exciting story.