I do this too, but not with the serial numbers.
The temperature in my car must be set to an even number.
Quirks? You think you have quirks? I am CAPTAIN QUIRK, people. In my old car, the stereo volume always had to be an even number, even if that made it a little too loud or quiet. I eat my M&M, Skittles, what-have-you in an orderly fashion, although the exact manner varies. Sometimes one color at a time, sometimes to even up each color. Sometimes I pour the little bag onto a piece of paper and I eat the pieces in a way that reduces the chaos of the patterm, eg, if a red one is sitting in a cluster of brown ones, I eat the red so that it makes a nice single patch of color.
When gaming, all my dice or game pieces are organized in some fashion. Sometimes by color, sometimes by type of die or piece, sometimes into little shapes.
You know those cardboard milk cartons that the “Open Here” on the top? I always open the other side. (To be honest this began as a way to bother a classmate who was horrified that anyone would open the “wrong” side.)
I always read words backwards, especially when driving. I like the ones where the result is pronouncable. Words like “Win” aren’t as much fun backwards.
I, too, prefer to sit with my back to the wall.
If a part of my body lightly brushes against something like a chair or low table, I have to rub that exact body part against the same object sort of heavily, like i’m scratching it. It’s not an itch, but if in a situation where I can’t do anything about it, it bothers me like an unscratched itch.
Whenever I go through automatic doors I do this little wave with my fingers, as if I’m opening them with the Force. It’s reached the point that I rarely notice I’m doing it any more.
I’ve gotten strange looks at work for doing that at the elevator.
When I’m eating a meal that has food items separated on the plate, I have to eat one food group at a time until it’s gone, and then move on to the next. Steak, baked sweet potato, and veggies? Eat the veggies, then eat the potato, and then the steak. Flavors should not intermingle in my mouth.
It’s not that extreme; if I’m eating shrimp scampi over linguini or something, I can eat the pasta and shrimp at the same time. It’s just when there are completely separated items on the plate. And no, I don’t like my foods touching each other.
Oh, and the only time this doesn’t apply is when I’m having meatloaf and mashed potatoes. Everyone knows that the only acceptable way to eat meatloaf (other than a sandwich, of course) is by taking a piece of it and then dipping it in your mashed potatoes, right?
Why would putting bank notes in your wallet in order be a “quirk”? Doesn’t everyone? How do you know how much you have if it’s all just in there randomly? Facing them might be considered slightly OCD (I don’t think so), but serial number ordering is going a bit far, IMHO.
I thought of another one I have: using a knife and fork, I use the European system, but left-handed, even though I’m a righty. In other words, the knife is in my left hand, fork in my right, and I don’t switch hands, per the American system. I don’t know how I picked this up. Perhaps my parents taught me the European system (my mother was born in Germany) and I didn’t do it “right.”
I have right and left socks. I can not wear them on the wrong feet. I will wear a right sock with a hole in it before I will wear a left sock on my right foot. My big toes stretch my socks and make a point. If I try to wear them on the wrong feet they wrinkle up under the smaller toes. I can not walk around with wrinkles in my socks. My mother says I did this even at 2 years old. I would make her help me take off layers of winter clothes, snowsuit and boots to remove a wrinkle from my sock.
While most of my CD collection is cast CDS, I also collect those cheap “Jazz for…” and “Classical Music for…” series. Those CDS have to be arranged by month and season. I spent a lot of time deciding which CDS go with Winter (December, January & February), Spring (March, April & May), Summer (June, July, & August), and Autumn (September, October & November). Some are obvious (Rain is April, Lazy Days are Summer, Holidays are December), some are obscure (Chocolate is Winter, Tea is Spring, Wine is Summer, Coffee is Autumn).
I just thought of this one, I wonder if anyone else has it:
I’m a door toucher.
Usually I try to open doors myself but sometimes someone else opens the door. When they do I have to touch it. I will wait for someone to pass or go out of my way to touch the door. I don’t do this to automatic doors or to doors that are already open but I do feel compelled to do this to doors that someone is holding open for me.
I have no idea why.
I count stairs and sidewalk squares. However, I do it by 3s up to 15 ( 3,6,9,12,15) and in a perfect world a street lands on a 12 so that the first curb (curbs count the same as a square) is a 15, then I start over again. If I scan ahead and plan, I can do other multiples of 15 to make this happen e.g 5-10-15 but 7.5-15 is kinda cheating. Driveways count as streets too.
On stairs the top landing or bottom should be the 15 as well.
Dear God. I do almost all of this stuff. Except shave my legs.
My personal quirk is TOE LASERS. Yes, you read that right. TOE LASERS!
If I’m sitting around with no shoes or socks on (and if I’m not wearing shoes I’m certainly not wearing socks- I hate seeing socks on my feet!) I imagine laser beams that shoot from my big toes, and wiggle my feet and toes in order to bounce my devastating toe beams off windows and mirrors in order to destroy my target (usually the dog, or a plant, or my girlfriend) as efficiently as possible.
I also often interlace my toes (top of foot to top of foot).
Gosh…I don’t have enough time to list all my quirks but I will list a few.
I can’t share soap. We all use the same but mine has a separate plastic container for safety.
I can’t put more gas in my car then it takes to count to 100.
I must have at least four dollars and four cents in my wallet at the beginning of the day. Four singles and four pennies. I keep a roll of pennies and a small stack of singles at home for this purpose.
I can not drink the last third of any drink and must either refill it or throw it away.
That’s enough for now.
I’m another person who can’t sit with their back to the door. Now that I’m in a new office and have my back to the wall, I feel a lot better.
Er, because I come from a land where banknotes of different denominations can be told apart because they are different both in size and colour.
You know, I knew you people were weird, but I didn’t fully grasp just how weird.
I think I’m going to have to give up the SDMB, on the off chance that these quirks are contagious. I don’t want to end up as one of those people who has to wash his hands 600 times a day and dies with 40 years of newspapers stacked everywhere in his house.
Excuse me while I put last week’s papers in order and wash my hands.
Well, that’s okay. Are the sizes in the same order as the denominations?
But in any case, isn’t it easier to tell how much you have when you keep all the like bills together?
Not everyone walks around knowing how much money they have in their wallet. I don’t. Not because it’s so much at any time. A couple of tens or twenties. Usually my ones and fives are just shoved in my pocket. When I go to pay for something I take a look and see what I’ve got, and probably use my credit card anyway.
I’m normal.
What? You don’t know me. You don’t know me!
My dad had that one. Unfortunately, he always chose “refill.” 
It’s not like I know to the dollar how much is in my wallet at all times. The point is that when you want to know how much you have, it’s a lot quicker and easier to add up when all the like bills are together. YMMV.