I think my generation was the last to use audio cassettes. Tapes came with an A side and a B side. You had to manually flip the tape over to listen to the whole album. B sides got a reputation as being filler but every so often you'd find a hidden gem.

Digital cameras make it easy to take hundreds of snapshots, multiples of every shot at every angle and every setting, since the cost of each exposure is essentially zero. But within the sea of photos you occasionally find something that speaks. And that is the meaning of the B sides.