Just about everyone knows about addons like Gatherer, which certainly streamline the process of looking for farmable nodes such as herbs and ore, but don’t really do much to make it less soul-crushingly boring. I used to do things like run Winamp or Pandora in the background, but the necessity of tabbing out plus the more frequent crashes made it pretty much something to do only for, say, fishing trips to rebuild my dragonfin angelfish supplies.
Enter Epic Music Player, which essentially functions as an in-game MP3 player. It overwrites whatever the background game music is there (unless you choose to play the game music instead), and lets you run a playlist from your own collection instead, complete with a rotation selection of little dancing avatars to rock out with you. Obviously I turn it off during raids, but it makes things like farming and running hither and yon to visit my several hundred grandparents more relaxing fun than mind-flaying boredom.
Protip: run an all They Might Be Giants playlist while getting the Alliance elders. There was something way too much fun about playing “Till My Head Falls Off” while charging through Ironforge. Playing “Whoomp There It Is” during a gauntlet zerg of Culling of Stratholme was a gigglefest too.