I don't know if I could ever be a bartender. I like the idea of being one, but it seems to me it's like the ultimate pop quiz in a very intense situation. People come in off the street and ask you for a Tequila Sunrise or a Negroni or A Slow Comfortable Screw Up Against The Wall, and you immediately have to know how to do them. Sure, you can stop and look in a book (I did that when I was a sorta-bartender at a restaurant), but a real bartender has to know how to make these drinks immediately, especially if it's a Friday or Saturday night. Though I guess it's like any other skill, you learn through practice.
Esquire has the four obscure drinks that every bartender should know how to make. I've heard of (but never had) The Aviation Cocktail, but I've never heard of the other three.