It's wrong to keep old food because it's probably expired.
Sally is making dinner for herself, but the only thing in her refrigerator is some funny-smelling Chinese takeout from a few weeks ago.
Sally wants to eat something.
Sally goes to the grocery store and buys some food to eat.
Sally eats the weeks-old Chinese food even though it smells funny.
Sally has a nice meal and is no longer hungry.
Sally gets horrible food poisoning and misses two days of work.