From the New York Times, an article about how despite all of Venezuela's oil wealth at a time of rising oil prices, there are chronic food shortages, empty shelves and long lines, as a direct result of government price controls (see photo above):

"Venezuela is one of the world’s top oil producers at a time of soaring energy prices, yet shortages of staples like milk, meat and toilet paper are a chronic part of life here, often turning grocery shopping into a hit or miss proposition.

Some residents arrange their calendars around the once-a-week deliveries made to government-subsidized stores like this one, lining up before dawn to buy a single frozen chicken before the stock runs out. Or a couple of bags of flour. Or a bottle of cooking oil. The shortages affect both the poor and the well-off, in surprising ways. A supermarket in the upscale La Castellana neighborhood recently had plenty of chicken and cheese — even quail eggs — but not a single roll of toilet paper. Only a few bags of coffee remained on a bottom shelf. 

At the heart of the debate is President Hugo Chávez’s socialist-inspired government, which imposes strict price controls that are intended to make a range of foods and other goods more affordable for the poor. They are often the very products that are the hardest to find." 

MP: As economic theory would predict in the graph below, when prices are set below the market-clearing level by government edict, shortages are guaranteed, along with empty shelves and long waiting lines.