1) I like to beat time. Not a weird habit but I tend to it really forcefully. To other people, they are wondering why I am slapping my leg.
2) When I go on the treadmill at the gym, I look at the time for math patterns. For example:
Time - 17:16
To me, I think - 1+6=7, 7-1=6. Sometimes I have established patterns I want. So for that example, it would be 8:7. Since I want things symmetrical, I wait until it gets to be 8:8 before picking a different ratio. So, I'd be satisfied when it reaches 17:17, 17:19, 17:26, etc.
It helps pass the time, even if I am listening to music.
3) I watch people's body language for every interaction in front of me. One of my biggest pet peeves is a boss who gives a limp handshake upon the first meeting. Even worse if they look down or start acting nervously when around someone. I also look people in the eye and am disgusted if they look down and around. It is a sign of weakness. The first time, I deliberately feel out the person.
4) I do the whole "think about conversations before having them" thing also. I think it is just that I have to think about these hypothetical situations, even if I know they will never happen. No, it isn't shit like having conversation with the prom queen or some shit like that. Like today, I was thinking of a conversation about quitting my job in the vein of The Simpsons (when Marge becomes pregnant with Maggie) even though I have no intention of doing so.
5) One of my newest hobbies is annoying tailgaters. I'm 200 lbs, bench 355, squat 445, muscular, and have very low bodyfat so I figure I'd be able to handle 9 out of 10 fights. One chick almost ran into me and was trying to get past. So I sped up to catch up with a slower moving car and blocked her for about two minutes. She was obviously frustrated but she was on a cell phone when driving, which only justified being an asshole all the more.