So, my step grandma has been in my life since 'forever' to me. (Becoming my step grandma in my late teens.) Her first husband passed away early enough that I have memories of them being together, but no memories of what he looked like. During one of our visits, I asked her what he was like. She said: "Oh, he was a lot like your father. Always ready with a laugh."
I couldn't have picked that out, because it was what I'd always known. So, at that point, I started watching for it. It was true! Even before the punchline, you can see that he knows it is coming and that he has a laugh ready to go right behind his eyes.
Then I started watching for this in my own community of peeps. It is less common than one might think - and it is really nice to be around.I guess that makes me grateful to have been around such a great sense of humour since day one. :)