Cats don't forget, even if some people do.
Next-door-neighbour had a kitten; cared for it for a few years. New baby came along, decided baby and cat didn't mix. Threw the cat out (literally). Cat came to live with us.
For a long time (couple of years) cat used to sit on the front lawn, watching 'his' front door open and close, watching 'his' people come in and out.
Now neighbour has moved, and cat has settled with us. But what on earth goes through an animal's mind? How does it reconcile being cared for, then NOT being cared for? Cats are sensitive and intelligent, but I'm not sure how they could cope with that.
Sorry, not that relevant to original post, except to say I'm glad, too, that cats find their people.
BB