The Left vs. The Right (Stereo Channels)

Humans love tinkering with existing things. When talking about music, you can always find new ways to listen to a song... Some examples would be something like an "Isolated Track" where an instrument (or vocals) from a song are isolated and played on their own (like this example of Smells like Teen Spirit with Just Kurt Cobain's Vocals). We also figured out that playing songs backwards sounds like the devil, like in Stairway to Heaven by Led Zeppelin. (We'll come back to that song in a second). Theres also even people who can take an existing song and make every instrument play the same note for the whole time, like in this example of All Star by Smash Mouth that got re-tuned so

that the only note played and sung is C. I personally love going on the internet and listening to my favorite existing songs in different ways (Mostly using isolated tracks) but I do have a second favorite way.

In every song, there are instruments or vocals panned left and right. This means that they were intentionally moved to be more prominently heard in the left ear, or right ear. Some songs do it to add punch to something... Some songs do it to "fit" more instruments in. There's no set reason to do it, but every song does it.