USA, 1968, hard bop / post-bop
Thelonious Monk – Underground: There is some underlying restlessness to this music (except for the last track), as if something is on the verge of breaking but never does. There is also a niggling notion of repetitiveness irritating* the ear at certain points.
*not to mean it’s bad, just a way of explaining the sound. If irritation is intended and done well, it can be a good way of communicating what you want to say.