I guess I've always thought of rejection letters the same way, that maybe there's some magic number, only I don't know what it is. This attitude saved me from a great deal of distress when I started submitting my childish manuscripts to editors and agents at the age of twelve, but is a little less comforting now than it was. Of course, a great deal depends on the style of the rejection. Of course form rejections are the worst, but there are nice form rejections that try to say, "we don't think it's for us, but maybe someone else will like it" and then there are the ones that just seem to say (in a polite way) "we just don't like it and you should give up now". Luckily, the one I got today was one of the former. Very nice without sugar-coating anything, which I also can't stand.
The worst rejection letter I ever received was in the check-box format. There was a list of reasons why they might not like a manuscript (not right for the list, badly written, spelling mistakes, etc.) with little boxes next to them. No signature, nothing. At least I didn't get the "badly written" box.
So thank-you to the agent who sent today's rejection, for being kind. Also for being fairly prompt and not leaving me on tenterhooks for months. I really do appreciate it. Now on to that magic number.