The little things are adding up to make the world's biggest brick-and-mortar retailer also the world's best brick-and-mortar retailer.Walmart (WMT 0.16%) certainly seems to be firing on all cylinders these days. Its second-quarter results were so solid, in fact, that shares reached a record high immediately following the recently released report. Moreover, based on Walmart's strong Q2 numbers, investors are deciding the economy and consumerism are healthier than presumed less than a week ago. That bodes wel ...