The thing that really causes me to get this feeling is songs that you used to listen to while around certain groups of people. You remember things that happened, and in some cases it's as if you relive an entire section of your life in milliseconds. I don't recall singular events, but individuals stand out vividly in my mind - almost as though silhouetted against my past - former hurt rises to the surface from unknown regions, and I have to stop to collect myself, to the point of having to pull over if I'm driving.

Music seems to do this much more vividly than the mere mention of names or events.