Driving in Puerto Rico is a lot of fun. A lot of people warned me that Puerto Ricans drive badly but the reality is that they drive in the subjective. That is to say, they drive as if the rules of the road are a bit fuzzy or open to interpretation or common sense. Instead of saying something like "You must stop for a red light" you should think of it as "You should stop for a red light" as in it is highly recommended and you usually will, but there may be certain times when you don't should common sense or circumstance dictate. This attitude is remarkably easy to adopt and in some ways makes more sense than mindlessly adhering to abstract rules.
Fondest memory: Puerto Ricans merge when they think they have enough room. You "should" have at least two car lengths to merge, but if it is a clear day and traffic is moving at a consistent speed, your car is small... hey, why not?
Favorite thing: Here is a map of the island which highlights not only cities, but El Yunque, and other points of interest.