When I'm working, I chew on pretty much anything that is within reach. I have to make sure that unsafe objects are out of reach, because I've caught myself chewing on sharp objects. I try to chew on pens, because that is the least destructive thing. I have tried to break this habit, but when I suppress it, worse habits appear, so now I just live with it. I also chew on buttons and my collar. All of my shirts have missing buttons, because I've chewed them so hard that I broke them.
I also play with scabs. It's a bad habit, but I find myself doing it without thinking.
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"Like lonely ghosts, at a roadside cross, we stay, because we don't know where else to go." -- Orenda Fink