Well, this took me back.*
I came across a file of my rejection letters as a (so very) young writer in the 1970's. I had forgotten I'd submitted to a couple >ahem< "other" markets who would publish science fiction and pay in 4 figures for them! [Hey, it was what Steven King did]. Wow, what chutzpah I had back then. :)
However, it was the little personal notes of encouragement that accompanied these letters, like "You write well. I hope we have another submission from you again soon" from then The Magazine of Fantasy and Science Fiction Assistant Editor Anne W. Burke (later Associate, then Managing Editor - and author - Anne Devereaux Wilson Jordan Crouse), of blessed memory, that stayed with me down the decades even when I'd long thought these letters were lost.
"Personal" rejections were more . . . personal . . . back then, for being written on paper and signed in pen.
Anyway, it is because of such small kindnesses, when I, in my capacity as assistant editor, send rejection emails to submitting authors, I always try to provide little notes of encouragement as well. Pay it forward.
* As I mentioned briefly in my prior post, but I felt it is deserving of its own. :)