I used to wonder why San Francisco could support so many corner groceries and Pittsburgh so few. Part of it of course is the density.... I used to wonder why San Francisco could support so many corner groceries and Pittsburgh so few. Part of it of course is the density. When people live close to corner stores, they have the walking traffic needed to survive. Part is the transit. A transit-friendly city brings more pedestrians who stop in the stores for a snack or newspaper. Part is the ability and creativeness of the store owners. Many specialize in one thing or another, cold cuts, salads or organic products.

That's not the entire story, however. San Francisco's corner stores have one advantage those in Pittsburgh (and Philadelphia) don't, the ability to sell alcohol. A six pack in San Francisco is just a few steps away for most people and many of the stores there offer variety not found in even a large outlet. One store at Noe and 17th in San Francisco specializes in Wine. The variety and quality of wine of varying price astonishes. There are even wine-tasting events.

Liquor sales in Pennsylvania cities are the exclusive property of state-run liquor stores. Beer is sold at private beer outlets and only available by the case (though a tavern can sell a six-pack). That's starting to loosen up with the state trying out sales in certain locations . Freeing the industry up and allowing wine, beer and liquor to be sold most anywhere would undoubtedly bless cities in the "State of Independence" (Pennsylvania's soon to be new slogan) with not only more readily available vice, but countless additional convenience stores and a ready supply of grocery items for city residents.