Seven Nation Army. I don’t care that it’s played on guitar with an octaver. It’s a song where the bass line became a folk song in some parts of the world (meaning the people who sing it don’t associate it with an author because it’s spread by word of mouth). Not the main melody or even the whole song. Just the bass line.
A band I used to play in would jam on it for like 20 minutes. You could literally pull randos from the crowd to sing it and the jam sections could go through just about any genre you wanted. We played it as reggae. We played it as punk. We played it straight. We played it as funk. It’s a really versatile line.
