Crappy/nonexistant local stations, low adoption of RDS. It comes on a lot of newer foreign cars, but not all station support it, and many stations won't do handoff, if they even have more than one transmitter. Many places are only covered by a couple stations, and your choice is country or preaching. Many places have no station that comes in clearly at all. Realize that I can drive for ten hours without leaving my state, and during that time there might be times when I don't see another car or so much as a house for 30 miles. And I don't even live in one of the huge western states with regions of virtually uninhabited desert, I live in Michigan.