Having a real wallet and a real book make me feel so well-prepared. So does going down Wikipedia rabbitholes and using a library card.
The trashiness of trash depends a lot on where it's been placed or displaced. These useful napkins were doing great in my glove compartment for a good long while, but it only took one rummaging encounter with the car manual for them to be cast down into uselessness. Under the seat? That's just a mess.