I can't remember if there's been one of these before, and my initial search didn't turn up anything. So I'm creating a new one.
I've been working on some designs. Most people, when I show it to them for feedback, say something like, "Oh, that looks nice!" Which is... flattering, yes, I guess -- but not really what I want. I want to make the designs better, not buid my ego.
I showed it to an ISTp and right away she started off with, "Can this part get squished up higher?" Then when I pointed her toward a general design element I was unsure of she gave a useful opinion on that, too. She warmed up to it then and gave a few more suggestions. Which is what I wanted.
So, yay for ISTps, who are fine with giving critical but useful feedback and don't worry about stopping to think about common flattery.