"Constructive critizism" is tough to take, that's for sure! I've gotten quite a bit of it here on this site. I have to admit, though, that I'm better for it.

Something that I apply when this happens is "STOP... THINK... ACT" ... rather than REact. If I find a smidgeon of truth, then I try to stay aware of what was critizised and work on it.

*Notice, I said "WHAT" was critized, not "WHO" (which would be me). I try to difuse the situation (within my self) by not personally internalizing what was said. Of course, it takes time and work to get to that point. That's when it's best to "become silent."