I just listened to a song that I immediately loved. But I won't learn it because it's 'way outside "what I do."
That got me thinking about why I DO learn certain songs and not others. Some of it is some variant of "I like it" but some is "my partner wants to sing it." A song can be silly if it's cute or it really swings or it's just fun to play. When I think about it, I don't have much tolerance for weak tunes or chords. I like it if the song suggests a novel way to present it as a duet. I like something that can be well-presented but I don't worry much about what the audience "would want." I assume my audience will like more-or-less what I like and that many grew up listening to these songs (fewer every year) and that's good enough. But that means I tend to stay inside the "old pop" or "standards" idiom with occasionally some ancient R&B or hillbilly or western added to the mix. I'm happy with that and I'll never exhaust it.
How about you?