I always wear the same t-shirt when I take a flight with my wife. I always wore the same trousers when I did stand up comedy in Hong Kong. If I have to make a speech I always write it on my hand and then never look at it. I have to have a particular pair of shorts when I do my early morning Sunday run.
If I don't do these things, the world has a habit of screwing with my plans. It's not that I think they're capable of altering my fate, but the absence of them makes it easier for mistakes to happen. If I have a different pair of shorts, I might not remember to take my keys with me because I won't remember to check they're in that particular pocket. If I don't write things down, I'll forget them. If I'm trying to decide which pair of trousers I'm going to wear, I'm devoting scant mental resource to something that isn't essential to making people laugh.
Well, I've had people laugh at my clothes, but those chuckles are few, far between and undeserved.
These habits-cum-totems of good fortune have an important role to play. They allow you to concentrate on what's important. If you know you're wearing your lucky socks, you can stop worrying about laundry and think about how you're going to impress people. If you've tied your shoelaces and undone them and tied them again you know they're not going to come undone. Just like Obama's famous lack of variety in suits: by removing the need to make a decision about something trivial, you can concentrate on deciding important things.