You leave the house with a $20 bill in your wallet, but after buying some helado on the corner, getting a gyro from the food truck, and breaking off the b-boys on the 2 train with a little pocket change, that Andrew Jackson turned into Honest Abe in about fifteen minutes. With your spending habits, the more currency you keep on you, the closer your bank account moves into the red.
While you're at it, get rid of your debit card, too. You can't be trusted to stay away from ATMs. If you keep most of your cash under the mattress like a real baller, you'll have more to your name. Your pockets may look like rabbit ears out in the streets, but you'll know you've got the bread under those sheets.