This #JMusicFriday is about #Memory eh? Since that can include things that give us memories in addition to songs about memory it really opens up a lot of options.
I'll do something that combines both. From .hack//Liminality (the OVA that accompanied the .hack PS2 games) composed by Yuki Kajiura: https://www.youtube.com/watch?v=tu5qxIlZt0Y
Not only is the music itself about memories with a sort of hint of nostalgia in its feel, but for me at least this brings up a lot of memories of much better times. Not just me personally, but even anime at the time just had a better feel for me with such great shows at the time. And Kajiura was making music for so much... I loved listening to her soundtracks while doing various things.
I realize this tag is normally used for vocal music, but this just fit too well.