I'm very fascinated in listening to what landed up to the creations of songs (such as demos and stuff like that) which is why I thoroughly enjoyed listening to Hawaii: Part II: Part ii (thanks @cheesewhisk3rs for making me aware of its existence)
Hell, even listening to older versions of the things I've made interests me sometimes
Also you sometimes stumble on gems like https://www.youtube.com/watch?v=wtPTubkMWtA which are so much better than the original version…