According to Tom Mueller, most of the extra virgin olive oils in supermarkets don’t meet the extra virgin olive oil standards. He investigated and found fake, smelly, and rancid oils.

For his list of the best supermarket olive oils:
Truth in Olive Oil

For more information:
Extra Virginity: The Sublime World of Olive Oil
by Tom Mueller
Extra Virgin Suicide: The Adulteration of Italian Olive Oil
by Nicholas Blechman