I once read that Nick Mamatas suggested every writer should read "slush" for a while. Sorry I can't locate the source...it's out there...somewhere on the interweb.
Great advice, really...even if I can't completely tell you why. I guess it helps to identify both successful and unsuccessful "patterns" in writing.
The hardest part is writing the rejection letters. (This topic was inspired by a recent post at Brenton Tomlinson's blog).
I prefer to send form rejections. I hate to admit that because form rejections suck to receive, but sometimes I really can't put your finger on what was "wrong" with a particular story. Sometimes other pieces did fit the theme of the publication better. Sometimes the story just didn't resonate for some reason.
But even worse than a form rejection, to me anyway, is a "personal" rejection that makes me question whether or not I should stop writing. And it happens. That's when I must remind myself, as all writers should, that the rejection was aimed at the story, not me. AND the rejection was only one opinion. AND sometimes the editor is just pissed off at the world when he/she/it wrote the rejection. It happens. If it held something useful, great. If not...it still served it's purpose/got the message across.
I've tried not to write those type of rejections in the past. I've tried to keep comments brief and constructive. And I always want any writer to know the rejection is only my opinion. My partner in "crime", Ed Lupak, and I agree on that.
Rejections, both ways, can be ashes in one's mouth...and I like my mouth ash-free.
But, while rejections--at least for me--suck to send as much as to receive, I second Mr. Mamatas's opinion: every writer should be a "slushie" for a while. You can't replicate the experience any other way.