I got a few bad/weird habits.
I pick at sores on my body, no matter where or how painful it is, and eat the scab.
I wash my hands fairly often. Any sort of grime/dirt/oil/smell causes me to wash them.
On a related note, I always wash my hands 4 times after using the toilet, then a 5th time about 5-10 minutes later to ensure the smell is gone.
I smell my hand after touching pretty much anything (Especially metal and dusty objects)
I use fractions to see how much longer I have left of something (Eg: Oh look I'm 1 sixth away from being done)
My computer volume must always be set to 24. TV volume is always set to 21 (Although the TV I'm more lenient with).
I only crack my index fingers.