Would you add $12 to a grocery basket just to qualify for a $5 discount?

The cashier pointed at my $38 basket. "Another twelve dollars and you can use the five-dollar voucher."

I went back for two packets of pasta and a jar of sauce. After the discount, I paid $45. I had planned to spend $38, so the saving cost me another $7 at the checkout.

The extra food isn't useless. We'll eat pasta, and the sauce is a kind we like. But we'd already planned the next week's meals, and there was pasta at home. My partner said I was being too hard on myself because I got $12 worth of groceries for $7. I couldn't quite explain why that still felt like spending I hadn't chosen.

Next time, would you take the discount only if the extra items were already on a future shopping list, or treat long-lasting food as a sensible stock-up whenever it fits the budget? I'm trying to distinguish a useful bargain from a coupon deciding what's in my cupboard.