I can only think of two reasons why certain songs are on my playlist while others are not. They either:
Those that do both ranks up higher, with preference given to the former item. Simple as that.
Not incidentally, these two factors relates closely to my measurement of good design, good advertising, good reading matter, and good whatever else. In those context, ‘challenging’ becomes ‘witty’ or ‘shrewd,’ but ‘telling stories’ are still telling stories. Without challenge, a medium will not caught any attention. Without story, it will fail to be remembered and savored.
PLEASE NOTE that while these pieces are all instrumental, this fact shouldn’t be taken as an indication that I listen to elevator music all day (though there are certainly times that I do.) I do think, however, that lyrics tend to blunt the ‘telling stories’ aspect of the song—because, duh, words can’t not tell a story.