UP: I
unironically adore
Fireflies by Owl City.
It was real popular in early to mid-2010. So I was 17, and this was around one of the "peaks" of my life with how stuff in general was just going great for me.
I, like many, tend to listen to catchy songs on repeat a lot when they strike my fancy. It did around that time, and thus became a mental symbol of that time. I had fun, I was in increasingly good shape (relatively speaking), I had just made new friends that I still have to this day, weather was great, life outlook great, all that stuff.
It became extremely melancholy tinged as my life went kind of to
purgatory the next year, with the worst part of it happening even in the
geographical location that I was in when I got truly hooked on the song first a year before. So everyone has some tunes that are very nostalgic for, but in some ways that melody is a sharp reminder of how my childhood ended while my early adulthood got stolen. So I still love it for the good times it represents.
Also makes for some great parodies/mashups