Single people, can you list things you do habitually that a reasonable prospective cohabitant might object to? You might have a boyfriend or girlfriend or you might not, but you do have a few things that you prefer to have a particular way around your house that may well have to have to change once you start sharing living space with your BF/GF. I suppose you could even be married, with your spouse spending periods of time out of the house where you do weird things that you don’t do when your spouse is around. Can you name a few of these things for me?
I spend a lot of time on the Dope.
I snore, I drool, and I grind my teeth, and that’s just what I do while sleeping.
I get easily startled, I have a permanent cough, I don’t like being disturbed in the bathroom, I’m scared of everything, I’m tired all the time and tend to get behind in chores, and I still find Rick-rolling funny.
Sometimes I sleep with the light on.
No shame in your game; rolling Rick makes me smile every time.
I don’t cook, except for the batch of_____________ that I make on Sundays to eat throughout the week and I am really not interested in having someone else mess up my kitchen / stink up my house.
I have the tv on all the time and usually fall asleep to it (of course if I had someone around, I probably wouldn’t need to have the tv on all the time).
Do NOT use my face towel to dry your grubby mitts; that’s what the separate hand towel is for.
I keep the a/c at 78 all year round except for the few days when it gets cold here.
I will bitch if you leave the water running while you brush your teeth.
Once or twice a year I cook buckwheat. My wife can’t stand the smell of buckwheat. She goes upstairs and shuts the door, and complains the next day if the house still smells of cooked buckwheat. I love buckwheat.
I sleep with loud white noise. Me and the wife love it (we graduated from small fans, to large fans, to “Hey google, play white noise”), but I imagine a sudden new bedfellow might really hate it.
I also wear arm braces when I sleep, which looks ridiculous and doesn’t lead to much spontaneous sex.
Non-sleep related? Nothing too out of the ordinary I can think of, either that or my wife has just gotten used to it.
I don’t flush unless it’s really necessary.
When driving, I like to change the radio station every few seconds.
I fold towels in thirds.
I have a bad habit of leaving dresser drawers open (drove my ex wife crazy).
Dishes ain’t get’n done until the morning. (They never sit for longer than over night tho’)
Lights out if you’re not in the room where they’re lit.
Open windows as often as possible - no one needs a/c below 90° or in low humidity.
Silence is golden - you don’t need music or the TV going every single waking moment.
Open the dishwasher as soon as the cycle is done - let the dishes air dry, dammit!!!
Other than that, I’m a peach to be around! 
If I need to burp, I’ll belch loudly.
I leave the bathroom door open when I use the toilet.
Like @Dung_Beetle, I follow the “If it’s yellow, let it mellow. If it’s brown, flush it down” rule.
I set my thermostat to 80F in the summer and 65F in the winter. Partly to conserve energy for environmental reasons, but mostly just because I’m cheap.
Like @WildaBeast, I leave the bathroom door open when I use the toilet. 
I leave the toilet seat up
I keep the water running when I brush my teeth.
When I go to bed I want absolute silence and darkness (except for the fan I have running on low).
Some reasons I’m difficult to live with:
I leave laundry unfolded on the couch, meaning to fold it, for weeks sometimes
I brew coffee in advance and then store jars in the fridge to drink iced or re-heated (rather than brew it when I want coffee–I’m impatient in that way.)
I’ve taken a perfectly fine sun room and turned it into a painting studio.
I almost always have at least one guitar sitting on the couch (crowded coach, I know) for easy access
I like to sing and as the man in Nashville (Richard Doqui, I think) says, “Girl, you jes’ cain’t sing”
One of the few rigidly enforced rules in Casa Pullin is that all commercials are muted. Whoever holds the remote is responsible for this, and will be relieved of said device if the voice of any saleshole enters our domain.
It’s part of a larger context of rules relegating electronic devices to second class importance. They are to be muted/silenced/ignored when people are interacting. Of course there are exceptions like ill relatives or family member traveling somewhere, but in most cases I strongly insist on banning electronic leashes for family conversation, dinner, games, etc.
I guess that would be objectionable to some, but my rule is you can have dinner with your phone, or with me. But not both.
Ooh, I thought of another one!
I have long hair, and when I wash it, it sheds. So I take the wad of wet hair and drape it over the shower shelf to keep it from getting into the drain. I mean to throw it away, but by the time I get done in the shower, I’m thinking of other things and the hair stays there all week. Plus I’m adding to it every day.
I play my music REAL FUCKIN’ LOUD.