Getting value for time is productivity. Up to you if value is in money or enjoyment. Your "logic" seems extreme. I'd have to have some irrational hatred for shopping before I'd spend even more on groceries to get someone else to do it. Similarly, I'd have to have some pretty strong feelings to love it so much I'd take a minimum wage job to do it in my spare time. I think the average person is going to fall firmly in the "if shopping for an extra 30 minutes saves me 20 dollars, I'm doing it" camp.