I, at the other hand, although ambivalent about the "progressive" label when applied in other contexts, was a big prog rock fan. A matter of tastes, I suppose.
For you, youngsters, prog rock (progressive rock) was a largely British musical genre popular from the late 1960s to 1970s. From the U.K. it extended its influence to other parts of Europe and Canada; while in the U.S. a few bands, like Chicago, occasionally managed a somewhat similar feeling.
From Camel's 1977 album "Rain Dances" (largely instrumental, in my opinion their best by far), the opening and closing tracks are variations of the same theme (note the pizzicato guitar, played by Andrew Latimer, in Rain Dances: the rain drops):
First Light (opening track):
Rain Dances (closing track):