Though I’m pretty sure everybody has fondness for the music they liked from teens through early 20s.
I definitely don’t. I grew up without access to music, so I only started listening to stuff when I was 18, but it still took me several years to figure out what I liked.
Not really a plot hole, but a missed opportunity. Dumbledore’s Phoenix could have shown up to help Snape - putting Harry in a mindfuck state as he would know both that Snape killed him and that Snape was loyal to him.