True story:
I once was at the grocery store and was buying four (4) 1/2 gallons of milk which were on sale for $1.00 each. The gallons were $3.49 each so it was a good deal. I had just put them in my cart, when this gal reaches in and gets the same stuff in gallons. She too, chooses 2 gallons.
I say to her: "You know, if you buy 1/2 gallons, they're on sale for a dollar each."
She says to me, "Yes - I know - but we drink a lot of milk at our house, so we need the gallons".
So I looked at my 2 gallons for $4.00 and her 2 gallons for $7.00 and said to her: "Yeah, that makes sense"