One of the facets of "Oklahoma culture shock", as some one recently put it, was how difficult it is to buy a drink out here. Buying a drink requires a bit of planning. Beverages that contain more than 6% alcohol can not be sold cold. You can either drink diluted beer or know a few hours in advance that you will feel like having a drink. Ever wondered why wine shops don't sell corkscrews? That's so weak-willed souls aren't tempted into sin, as if having to buy a corkscrew at Wal-Mart is going to deter the determined drunkard.
Liquor stores are closed on Sundays. Considering that all stores (except the 24-hour-7-day variety) are closed on Sunday mornings, that is only to be expected. This means that you stock up on your wine on Saturdays. More planning.
Our legislators and their assorted lobbyists, who know what is good for us, have made getting a few drinks out here in Oklahoma tougher than getting religion. Apparently, that is the idea.