In my case, because I apparently do not know what to buy and always buy the wrong stuff. We (2 adults who rarely drink milk) now have two gallons of milk in the house because I bought milk from Walmart for $2.07, but I was apparently supposed to get the organic, non gmo, additive free milk from Whole Paycheck for $6.99 because that is what she bought the next day.
I only got milk for a recipe and bought a gallon because I figured it would be nice to have some milk for a change, but she corrected my “mistake”.