Thick Skin

I've seen a lot of job postings lately where the company is looking for candidates who are "stress resistant"; or who are "comfortable with ambiguity"; or who have "thick skin". When I was making this piece I was thinking about how these descriptors sound like euphemisms for people who won't complain or speak up when something is going wrong. But I could be wrong. Maybe there is a way to develop that kind of thick skin. If you know how, will you teach me?