How do people in court remember details from years ago?

It always baffles me that people in court are like “I remember saying this to this person at 2AM ten years ago. I forget conversations I had months ago, I couldn’t tell you what I said to my friend last year on this day. I’m also a waiter and a bartender and kinda streamer so I’m constantly talking to people so it’s hard to remember everything I’ve said to someone