I am the kind of person who would sniff the pages of a new book. I've had this habit since I was a kid. I don't know what's with books that makes them smell so good. It's really addicting, and I suggest you try it.
Whenever I am thinking, having a short break, or even just a pause from doing something, it's likely that I'd be biting my nails, consciously or unconsciously. There's this weird satisfaction of having to tear those nails off or the side skin of my fingers using my teeth. This one I am trying to let go, as it isn't quite good to have little wounds on my fingers, other than being in pain for some time, it's also kind of embarrassing when people begin to notice.
When walking along the paved sidewalks on the way to our apartment, I have this habit of not only counting the steps I take from one street lamp post to another but also making it a point to have my steps equally numbered. The number of steps I take from post to post should be the same because they are equally spaced, right?
These are just some of the quirks I initially thought, but I know I have many. LOL