Money is all about opportunity cost. Every time you spend on something, that's something you can't spend on something else.
Dan ArielyDo you know how much money you would save if you changed your light bulb to compact florescent light bubs? How much would you save if you decreased your temperature of your house in the winter by one degree, or increase it by one degree? We just don't know these numbers, but I think displays could make it a memorable change in terms of attention, and also help us translate it in terms of concrete ways on what you can get.
Dan ArielyWhat people do is they pay the small loans first. Why? Because they enjoy making the number of loans smaller. But of course it is a very ineffective way to pay debt down.
Dan Ariely