Why Do Some Investors Watch The Pennies Carefully While Letting Dollars Slip Through Their Fingers?

On food purchases alone a wise shopper can often save $100 - $300 per month by buying carefully, shopping at Costco, comparing prices, etc. This shopper may spend a few hours more each month, compared to the shopper who just throws food items into the shopping card without even checking the prices, but for the cost conscious shopper this is time well spent. The careful shopper gets as much satisfaction from getting a good deal and saving a few dollars here and there as a spendthrift...