Sometimes the most unexpected people, or those whose company you prefer the least, end up having the best memory power. Or the worst, depending upon how you look at it, and the memories in question. We would rather remember that time when we earned a pat on the back from a teacher than when we faceplanted the floor, courtesy a careless stranger, right?
So such distant acquaintances or foes(worst case scenario, God be with you) regale your companions with some long forgotten incident while you are left fumbling in the dark, either preferring not to remember, or wondering how you could ever forget.