I have this thing I do with the big toe on my right foot. I apparently lift it when I'm walking so that it presses against the top of the shoe; I know this because I sometimes develop a hole in the top of my right shoe right over the toe. I've got a pair of sneakers that I bought cheap at Wal-Mart a few months ago, and already they're developing the same hole. Right now, it's more like a cut; invisible until I lift my right foot and then the white of my sock flashes briefly through the hole in the black shoe. When I curl my toe down, the slit closes and the white disappears.
So now I'm very self-conscious when I walk, trying to consciously turn my toes down. It's a pain in the ass.