An old acturian at my current job usually tease new developers that they are just like dentists - never satisfied with anyone elses work and always suggesting serious rework that is critically important.
But as in every job dentists also feel pressured to point out other people's lack of quality work to promote their own. You'll see this in the IT guy who immediately recognizes that whatever the previous one did on your computer was amateurish and they can do it better, same with the electrician, the plumber, the mechanic, the plastic surgeon, etc.