A mysterious and long-acknowledged attribute of Greatest Hits albums is that they always seem to be missing one or two of an artist’s truly great songs. Go through your collection and see for yourself; I’ll bet you will be hard-pressed to find a “Best Of” collection that doesn’t have at least one notable omission.
In the case of the Bar-Kays, they have at least FOUR Greatest Hits-style albums which all leave out “Soul Finger”, the group’s biggest hit single, reaching #17 on the pop charts in 1967. To be fair, there are two Bar-Kays compilations that DO include “Soul Finger”, both of which were released on the K-Tel label (the other versions coming out on Island, Mercury, Def Jam, and Fantasy Records). This being the case, I can only imagine that the “oversight” on the other four related to publishing rights, which would be unfortunate. After all, while I like some Bar-Kays funk, I’m not so sure they’re deserving of SIX separate Greatest Hits albums.