@Zoey You are right. People won't remember even half the things said. It reminds me of this one time (1 year after high school). A girl was talking to me because she recognized me from school and seemed very cheerful. I got her name wrong (very wrong) when I spoke to her and I didn't remember her face in the slightest. I drove away.
There are some times in my life where I get deeply worried about my long term memory. Particularly when it comes to people. Some people ... okay many people I knew ... okay the majority of people I knew from high school are less memorable than a shampoo bottle I forced myself to memorize 5 years ago. It's terrible but a true story.
I barely remember my mother's birthday, but her birthday is the only one I know other than myself so she must be important. Yes, my mother is very important.
Despite what you may think, my head works very well when it comes to academics, but when it comes to people ... I think it's due to apathy, which is strange. I care about what other people think of me, but I don't care about them specifically at all to the point that if I don't see them daily I would likely forget their entire existence, immediately, forever.