Every week, rejection letters from my past. Because the hurt goes away after a couple of decades.
Remember: My rejection history goes all the way back to ancient times, when you actually had to mail in your story for rejection! If you wanted the manuscript back, you had include a self-addressed stamped envelope with sufficient postage to get it back to you. For me, it was easier and cheaper just to include a regular business-sized envelope for the inevitable rejection. Printing out a new copy of the story for another publication was no big deal.
But I like that Michigan Quarterly, in addition to scrawling a pleasing and somehow jaunty “Sorry!” along the bottom of their form rejection, also took the time the scratch out the word “enclosed.” It’s that sort of attention to detail that I admire!