Milk. Milk goes bad on me unless I am being really heroic about it's use, have purchased a very small container of something ultra-pasteurized, AND am feeding it to friends. Two out of three means I am only wasting a little bit. One out of three means I am wasting the milk AND the coffee I have attempted to put it in.

I mean, right now I am suspicious of everything in my fridge, but that's neither here nor there.