Weird habits? Well, hope you've got time, 'cause this could take a while! XD
1. When I sit at my desk, I always fold up my right leg and tuck my right foot in under my left leg. Never the other way around. I tried doing it the wrong way around, and it felt deeply, deeply wrong.
2. I hold my pen like this:
3. I tell myself stories. Like, out loud. All the time. The moment I find myself alone, I start telling stories. Part of it is me figuring out parts of how my comics should go - like, trying out dialogue to see if it works, pacing through fight-scenes to get the choreography right, doing trial runs of scenes to figure out the best way to tell them, etc. - but a lot of it is just an incessant need to tell stories.
I've got fictional universes in my head that will never turn into stories I share with other people - they're just there to entertain me, or help me kill some time.
It's also a way to cope with stress and anxiety. When I was young, my parents used to read bedtime stories to me. I just kep the habit up by telling those bedtime stories to myself. It helps ease me into falling asleep.