It is not always the case that a random conversation is funny. One might be enlightening, yet convey information that, while true, is not the sort of thing we want to know. But we may need to know. Some conversations are heart-rending.
The essentials of this story are true. Of necessity identities are masked.
Spouse and I were in the local eatery, seated in a booth. The person approached the table, beaming smile on face, reached out and touched me on the left arm. I spoke this person's name, said, "It's good to see you!" The response was, "I can't remember your name."
The individual was an employee and confidante for many years. We shared office space. We worked together to achieve common goals. I mentioned that we had worked together a long time. "Oh," was the response, "I know that. I know who you are, I just can't remember your name. I have Alzheimer's and it is quite troublesome, sometimes."
At this point my spouse came to the rescue of these two long-time friends and introduced me by name. "Oh, yes. Of course. It is good to see you again."