I would presume it’s entirely subjective and the significance of each song is encoded in the context of life at that particular time.

There were a couple of months this year where my kids wanted to listen to Sesame Street “Letter L” and “The Word is No” while commuting. Hearing those songs on a playlist would remind me whatever was happening, but would have absolutely no significance to you.

All my monthly playlists and the yearly best-of are public on my profile:

https://open.spotify.com/user/sebastienbarre