Songs and circumstances:
Sweet Caroline: during a family road trip from Michigan to Florida on vacation when I was young -- one of the first songs I remember.
American Pie: My friend Mike in 7th grade (1972) bothering his friend Lewis with it on the bus to school in Michigan.
Age of Aquarius: We learned the lyrics in art class in 7th grade, same art class where we learned to tie-dye t-shirts, and where the teacher complimented me on my eyelashes (which of course would probably not happen nowadays).
Bowie's Fame: High school, St. Petersburg (Florida, not Russia). Noticeably often when I went in to the cafeteria on break between classes, that song would start to play. Omen, coincidence, mockery, or appreciation? I do not know.
Another great song from those high-school cafeteria days: Black Water by the Doobie Brothers.
Oh Very Young: I voted for that to be the theme song for the senior prom, but Stairway to Heaven won, dammit!
Almost forgot about this very important one from that time: "The Raven" by Alan Parsons Project, heard on the radio in my parents' home in St. Pete.
And the first chords from Manilow's "Could It Be Magic" and Parsons' "Wouldn't Want To Be Like You" got me interested in playing the piano (to little effect).
Later in life, on the last day of my month in the U.S. Army (too nearsighted), I left with a harmonica and the album Turn of a Friendly Card.
Life During Wartime (Talking Heads): Painting my parents' house in Mankato, MN.
In Mankato, MN, I bought R.E.M.'s Murmur based on a little one-column-inch or so review in Stereo Review (very early 80s), and also Sound Affects and The Gift by The Jam.
When I lived in Gainesville, FL, there were some songs I heard when out and about that I asked the DJ or someone at the shop about, to ID the song:
Drive by R.E.M.
Strange Kind of Love by Peter Murphy
Mighty Joe Moon by Grant Lee Buffalo
I was able to see many live shows by Emperor Moth there back in the day. The First Night and Three Will Weave are standouts for me.
The first two record albums I bought in Gainesville were on a trip to visit friends before I eventually moved there: "Hounds of Love" and "Lodger".
A few years later I asked a long-haired employee of a local record store if he could recommend some psychedelic music. He kindly suggested "Screamadelica" by Primal Scream and "The Aunt Winnie Album" by Bevis Frond.
In Gainesville I also got some albums by Screaming Trees and The Waterboys, and Mental Jewelry by LIVE.
And one night, long ago during a UF Homecoming show (the night before the homecoming game for the University of Florida Gators, an American Football college team), one could hear, miles from the stadium, Steve Miller's "Fly Like an Eagle".