I probably qualify for HSAM. I'm often reminding people of how we met, or a relevant conversation or interaction, and I can read them back what we talked about, what we ate, what the weather was like, those kinds of details. It's not as complete as a lot of the examples I've seen, where you can name a date and the person can recall everything, but I definitely haven't met anyone with a better memory, on average, than I have - with the possible exception of my mother, which suggests it's to some degree genetic.