Think MasterCard.

Cost of ice cream: $5 a week
Interest rate, compounded quarterly: 12%
Years to eat ice cream, assuming diabetes or heart disease don't get you first: 50
Not having to hear, "I want ice cream! Give me ice cream! Feed me!": priceless.
There are some things in life money can't buy; for everything else, there's MasterCard.

Sometimes extreme frugality just isn't worth it, even if it's going to cost me $822,047.39.