I can already sing and play the guitar, not brilliantly but idgaf, so the Spotify one is really tempting. But I learned to play the Guitar from YouTube, and also how to speed solve a Rubik’s cube and pick a lock, so that one would be super useful too. In fact I could just type in “How to play X song on the guitar”
So one of those two I guess, probably the YouTube one because job interviews would be way easier after a quick scroll through the thumbnails of a quick search before going in.