Yes, Alanabit, I was going to mention "Moon River." Someone told that story to me after someone requested the song on New Year's Eve. But I couldn't remember for sure whether it was Mancini, the director of the movie, or even lyricist Johnny Mercer himself who thought that a line like "...my huckleberry friend..." would never be accepted by the public and wanted the song cut from the movie! Then it won the Oscar for best song that year.
And, Jerry, I'm with you about using the set list as only a guide. I use mine mostly to remind myself of certain songs, so I won't have that slap-my-head-and-say-"Oh-s**t phenomenon when I finish a set and realize I've omitted the perfect song for that gig. Not only do I toss set lists aside when I'm reading the audience differently, but if I'm doing a story song (especially one that's like a joke with a punch line) and if becomes obvious everyone's using me for background music, I may cut the story short, to some workable ending, and move on to the next song, with no one being the wiser! Then I can use the song some other time when at least some folks are paying attention. :-D
Again,Slicker, ya gotta give a song a reasonable number of chances to click with folks, or maybe to find its audience.