Or they don't feel like getting a bunch of $5 bills for change? It's easy to just take a $20 bill (or two $10, four $5, etc.). Most ATMs give $20 bills; so, tha

Or they don't feel like getting a bunch of $5 bills for change? It's easy to just take a $20 bill (or two $10, four $5, etc.). Most ATMs give $20 bills; so, that's what a lot of people have. (They probably don't get too many $50 or $100 bills for parking.)