Curiously appropriate subject to post on a saturday night…
Album Filler are songs that take a perfunctory, Strictly Formula stance on creation in order to have something distinct to fill in some time. They’re usually straightforward, unimaginative, and otherwise forgettable. Of course, it isn’t set in stone that a song will suck for being filler. Just as how some of the most beloved episodes of many a TV show are quite intentional filler, some of the most popular songs were explicitly created as filler. A famous example of a filler track gaining large prominence is “You’ve Got Another Thing Comin'” by Judas Priest. This is one of the causes of a Black Sheep Hit.
via TV Tropes.