I’m glad other people have experienced the “untangling” phenomenon.
Most of my OCD behavior was from my childhood.
Let’s see here:
If I was riding in the car and could see the dashed lines in the road, I had to mentally weave in and out of each one. I’d work myself into a frenzy with my eyes, sewing some huge invisible thread in between each dash.
If I did something that in my mind seemed to “favor” one side of my body, I had to repeat the motion with the other side so they didn’t get jealous of eachother. Like if I bumped my hand accidentally hard, I would have to “trick” the other hand by hitting it slightly so it wouldn’t feel bad. Or something.
This is partially responsible for my semi-ambidexterity. Same the “tangled” feeling.
I would periodically choose one obscure word and have to say it every day, and if I forgot to do it say, for a month, I would shut myself into a dark bathroom and repeat the same word 30 times.
I will visually divide large quantities of any object into 3’s, 4’s, or 5’s, whichever is more visually pleasing. Which is perfect for counting pills at work, as I use 5’s to group them. And although they are divided into 5’s, they are not “5”, they are 1. If I am counting to 30, I count 5’s to 6.
All of my clocks have to be exactly synchronized, doubly so if they are digital. I once had 4 digital clocks in my room set so closely together that your eyes could not dart across the room fast enough to see the numbers change. Between any of the 4. 
I went through a phase where I moved the furniture in my room until it felt right. I don’t know how or when I acheived it, or maybe I just got tired of lugging solid-oak furniture around the room every weekend.
All the books on my bookshelf must be arranged by height or the amount they stick out of the shelf, it’s hell to figure out if I should organize from tallest to smallest or deepest to shallowest because some tall books are shallow and some deep books are quite short. On top of that they have to be arranged in order of genre, i.e. they have to flow into one another. Vampire books, medical books, psychology, languages, translating dictionaries, history.
See?
Makes sense to me.
So take the genre-organizing in addition to the size organizing, and it is a wonder that I have a workable bookshelf.
If I am packing something, it has to be the most tetris-tight packed box possible. I have the ability to move in just a few strategically packed boxes, and those boxes are all impossibly heavy. If I see empty space I will find things, things that don’t need to be packed, like wadded-up tissue or paper towels and shove them in there.
I know there are more. I’ll come back when I realize them.
-foxy