I have a single dollar bill in my wallet. That’s it. It’s lonely. It’s been the only cash in my wallet for 5 days now. I think about getting a soda or a bagel and then change my mind. Is it because my wallet would then be empty, or because I want to hold on to this dollar for as long as I can? Why don’t I just go to the ATM and get some 20’s to share space with my single Mr. Washington?