I saw an old boyfriend today, from 24 years ago. I only got a glance at him walking across the car park, as I drove past in someone else's car. I had to double-take because I thought he was in the Caribbean, so he was completely out of context. But it was definitely him; despite the very grey hair, I'd recognise that smug smile anywhere!
Part of me wanted to stop and say hello, but more of me didn't. What would we talk about? Actually I know what he'd say, and it would make me uncomfortable and wish I hadn't spoken to him.
Some people are best consigned to history.