You hate to waste food. a. Even if you're totally full, if someone says they're going to throw away the leftovers on the table, you'll finish them. b. You have tupperware in your fridge with three bites of rice or one leftover chicken wing.
You don't own any real tupperware -- only a cupboard full of used, but carefully rinsed, margarine tubs, takeout containers, and jam jars.
You have a collection of minature shampoo bottles that you take every time you stay in a hotel.
The condiments in your fridge are either Price-Club/Sam's sized or come in plastic packets, which you save/steal every time you get take-out or go to McDonalds.
Ditto paper napkins.
You never order room service.