The ideas about criticism that Andy Rutledge puts forward in this article are true not only of visual design, but any other form of criticism as well. They’re worth reading, especially if (like me) you’re a n00b at something and thus there’s lots and lots of fair criticizing to do.
I’m still having a terrible lot of trouble with “criticism of your ideas is not inherently criticism of you”, to be honest.
Oh, so am I! That’s half the reason I linked to this — so that when I do my link cleanout trawls I can reread the article and go, “OK, moron, now start behaving.”