Hugh Pickens writes "Ever bought something from Xbox Live Arcade? The first time, you may have been a bit bamboozled by the process because Microsoft doesn't just let you put $15 on your credit card to buy a new game; purchases are done in 'Microsoft Points' that you deposit into a virtual wallet and you use the points to buy stuff. 'Gamers possessed of equal parts suspicion and curiosity may wonder why our gaming overlords adopted such a strange system instead of just letting us pay real money for our purchases,' writes game psychologist James Madigan. He says the real reason for Microsoft Points is that sometimes you are going to have some points left over in your account. Leaving money on the table or in your Xbox Live account makes most of us a bit uncomfortable (PDF) because it feels wasteful. 'It's similar to overeating at a buffet or doubling your paper towel use after buying the 124 roll jumbo pack,' says Madigan. 'Even though you could just let those paper towels or Nintendo Points sit there until you have a good reason to use them, spending real money on something else seems wasteful.' And Microsoft isn't the only one – Sony and Nintendo have similar systems, and Valve has even rolled out a 'Steam Wallet' for in-game microtransactions."