There's no secret to how a large number of the population orders wine at a restaurant. If you don't really know what you're looking at, you pick the color, look at the prices, and go straight for the second cheapest bottle.
Makes sense, right? The assumption is that the cheapest bottle probably isn't very good, so if you pick that you don't know anything about wine and you're probably cheap. Disregard the fact that you really don't know much about wine, or at least you wouldn't ever be able to tell the difference between a $30 and a $34 cabernet ... assuming that the restaurant is pricing the bottles according to quality, or even what they paid for them.
Unforunately for you, this sneaky little trick of yours isn't new or unique to you. Everybody does it. Seriously. So imagine now that you're running the restaurant. Knowing that regardless of what the wine is being second cheapest probably makes it your biggest seller, how would you price your wine list?
Restaurants have used this bit of psychology against patrons for years. Rather than pricing the wine list strictly based on what they pay for a bottle, the cheapest bottle will be priced as the second cheapest, making it the bottle with the largest markup.
So the next time you're at the restaurant and you really don't know what you're doing or care all that much about what you end up drinking, just go for the cheapest bottle, there's a good chance it's better than what you were going to order and you're not fooling anybody!
BONUS: This Banned Grey Poupon Ad is Hilarious!