I just got a rejection, the first in ages. That sounds a bit full of itself, but mostly it's because my submission rate has fallen to practically zero in the past year, and I've often been subbing in response to a direct request, so I've been more likely to score an acceptance.
Anyway, rejection. Funnily enough, it no longer raises even the littlest nosedive of disappointment in me. Why? First of all, Kristina Wright's excellent blog post on an editor's job and how stories are chosen. Read it here. This wonderful article really helped me to dispel that lingering sense of persecution over rejections. I read it and finally really got that it's not personal.
Secondly, and this will sound maybe a bit odd: I subbed a story that I was unsure of. That I was experimenting with, taking a chance on. I'm happy that I took the risk, tried something new, happy that I failed, in essence, because it means I challenged myself. These days I have so little writing time, I only want to work on things that push me. That matter. That may fail. I'm not interested in publishing for the sake of it anymore.
Lastly, it helps when a rejection is nicely phrased. Yes, even a form rejection can be done with grace. I do wish all editors would be so thoughtful.