When everything fails, get to the nearest shopping mall and buy the cheapest (and the most decent) shoes you could find there.
I did exactly that after the job interview last week. I was the last person to be called in and when I get inside the room, I just felt defeated by the two previous candidates.
I left the building. A little crushed. Light up a cigarette. Order my latte at Starbucks. And then I saw it. Right across the escalator. A shoe store was having a sale.
Just like that... Everything feels A-okay.