Wright's Law of the Random Shuffle: All playlists contain one obnoxious, irritating song that you thought you enjoyed when you put it on there but since have determined you dislike, intensely - however, you are too lazy to remove it. If you put your player on random shuffle, the player will ignore the other two hundred and fifty songs on the list and repeatedly come back to the one tune you can't stand. Over and over and over.
The songs you really want to hear will never come up. Ever.