She didn’t pay for her hamburger, so why should she tell her what to do with it?

Food waste can be a sensitive issue for many people. If you grew up food-insecure, you might be one of those people who save everything and never let a single scrap of food go to waste. Someone with the same background could turn out the opposite, refusing to save leftovers and eating like a king at every meal, because scrimping and saving reminds them of the endless leftovers from their childhood.  

It’s work acknowledging that not all leftovers are worth saving. If you’re eating out at a restaurant before a movie and you have to haul your leftover buffalo wings into the theater to marinate in the room-temperature air for a couple of hours before you can go home and refrigerate them, you might as well have just left them at the restaurant. You’re going to create a lot more waste if you eat food that’s been out for too long than you would’ve if you had just thrown it out, if you know what I mean. Also, some foods don’t keep even if they are refrigerated immediately.