I love reading about this guy admitting his neuroses to us, then not to his friend. I love discovering that my own physical oddities have other matches in the world.
I'm okay with stepping on cracks or colors, so long as both feet do the same thing. Like if the left heel hits a crack, it is important that my right heel hit soon in the same place. if my normal walking pattern (especially when hindered by keeping pace with friends) doesn't achieve this, then I have to do a quick little half-step to switch my legs, and then my left foot will be evening itself out by hitting all the spots the right foot got.
But I'm not compulsive about these things or anything. It's not as though in college I actually switched which thumb would be hitting the spacebar or anything. Surely in my final year I couldn't have decided that my right thumb had enjoyed years of thumb-spacebaring, and enough was enough. It's just that the left one feels more natural, that's all. There is no deep hidden secret.