Mine is having to do something else while I’m brushing or flossing. I can’t stand just sitting there in front of the mirror while I brush and floss. I’ve got to read a magazine article, or watch TV, or do anything else. Otherwise I feel like I’m just wasting time that could be otherwise valuably used.
What’s your idiosyncrasy?
I hate not having something to read when I’m going to the bathroom unless I REALLY have to just go and get out of there. If I’m caught somewhere without a book or magazine lying around, I’ll pull chemicals out from under the sink and read their instructions. In a pinch, I’ll read things I have in my wallet, like receipts.
Redundancies. They make me break out in hive.
That’s right, just one big giant hive. I’m weird that way.
Could ‘weird idiosyncrasy’ be the same as ‘Odd Compulsion’?
Off the top of my head, my similar idiosyncracy to the OP is reading while on the toilet. Even if it’s the back of the toothpaste tube, I must read or study something.
If someone is walking behind me, at a similar pace, I feel compelled to make an excuse to stop so that they can pass. I hate when people are walking behind me, edging closer.
I also hate it when I’m walking a long, comfort zone intact, when someone who was stopped at a window suddenly starts walking at the moment I get near them. So that they are firmly within that comfort zone. I hate that.
Oh wow, I do that too! I’ve read catalogs, books, magazines, air fresheners, tile cleaners, soap bottles. . . EVERYTHING. I thought I as the only one.
Readers on the Can, Unite! 
We have multiple bookracks in both our bathrooms around Casa Silenus.
One of my other idiosyncrasies is that I am incapable of walking throught the hall between the Counselling Office and the Main Office without drumming my fingers on the counters. Both sides. Three full drums with each hand. Both directions, if I come back to my room that way.
It’s a minor compulsion…I can deal with it if I have to. But I feel weird if I don’t.
When I have toast with some combination of peanut butter, jam or marmalade, I put the butter on one side of the slice and then turn it over and put the peanut butter and/or whatever on the other. I’ve been doing this since I was a pre-teen, when one day I had a revelation that I could better taste the butter this way!
When I saw what was in the the thread-preview I came in exactly to say what’s been already said. I absolutely must have something to read in the bathroom. It doesn’t matter what it is, it just has to be words. Seriously - it can be French. Actually, so much the better. How else would I have learned what “nettoyage” meant?
Idiosyncratic, too.
TellMeI’mNotCrazy I love how, every time I see your name as most recent poster, it always seems perfectly appropriate for the thread
Well, actually it would be this. I didn’t know anyone else did this but me.
I cannot stand still and brush my teeth. I wander around and do stuff like pick up stuff or put stuff away, etc. Whatever I can do with one hand. It drives my son nuts.
I can’t sit directly behind the driver of a car, the very thought makes me ill.
I’m also a bathroom reader, I’ve been known to pick up a old newpaper if nothing esle is around.
I prefer to eat the traditional Thanksgiving Green Bean Casserole cold.
The ridge on the pen’s cap must always be aligned with the writing on the pen’s barrel.
When my dog sneezes, I usually say, “Shneezes, Ned Schneebly, shneezes!” Ned Schneebly is Jack Black’s roommate in School of Rock, but I’m not sure how it became associated with canine sneezing fits.
Another bathroom reader. I always have a stack of books in the bathroom.
I also cannot poop in any other bathroom other than my own unless it’s a dire emergency. Hotel room bathrooms are ok, as long as it’s only my sweetie and I staying in the room or I’m alone.
If I sat and thought about this topic for a while, I’m sure I’d come up with quite a few I have, but these are two of the biggies. chuckle
I have to have a Chapstick with me at all times. If I go out and realize I am Chapstickless (rare, but it happens), I must buy one immediately, even if it makes me late for work.
I have to chew gum after I eat. It’s not necessary, but if I eat something that I know is going to make my breath smell funky (including cereal, chocolate, what have you) or if I feel full, I need gum right away or I obsess until I get my hands on some.
I also compulsively eat altoids. I can’t eat just one, I have about a third of the tin at a time.
Tugging on my left earlobe when I’m deep in thought and at the computer.
Giving my toothbrush a hard rap on the sink to knock off excess water before I put it back in the cupboard. Just one rap.
I do this too.
I’m also a compulsive reader. If I’m at someone else’s house, I’ll read the cleaning supplies under their sink. If I’m at work, I read the can of air freshener.
This is the worst part of college for me. I can’t crap if there’s someone else in the next stall or brushing their teeth or something, and also I somehow always have to crap when the bathroom is being cleaned. 
I have to strategize. The bathroom on the second floor of the library, I’ve found, is the best pooping location because no one is ever there. It’s a bit of a walk from my room, though.
I’m like you other folks who can’t poop in anybody’s bathroom but my own, unless it’s absolutely necessary. And I can’t do it if anybody is in the next stall, or even in the room. And I have to be reading something. Also, if I’m having to go at work, I can’t stand to stink up the joint. Drop one, flush one. Why? Walking into a bathroom full of the stench of somebody’s having just voided their bowels makes me want to throw up.