Cool idea for a thread! I have so many memories associated with Ayu's songs, but here are some that immediately come to mind for whatever reason.
Trust -
This was the first Ayu song I ever heard. One day I downloaded it off of napster (lol so long ago..) and I was so struck by earnestness of her voice (after I was like "omg so squeaky" XD). I remember spending hours after that printing out and drawing pictures of ayu... I still love to draw her!
Trauma -
I'm pretty sure this is the second song I downloaded, and the first song I learned the lyrics to. One night I stayed up til morning memorizing them... it was so hard but I wouldn't stop until I could sing along. I think doing things like this helped me develop an ear for what "sounds right" in Japanese and made learning the language later on easier. So I look back fondly on that night it started
girlish -
My family and I were on a road trip (I was like 11 or 12) and of course I was miserable

. This song made me feel better so I played it on repeat on my cd player. At some point I played it in the car's cd player and my older sister even said she liked it (which is oh-so-important at that age). But I also threw up when we were driving through the mountains so it's associated with that, too :/