For TrulySkilledProgrammers, source code is a very important tool for communicating with other programmers, and even with our future self.

As opposed to:

In my experience many "TrulySkilledProgrammers" are below average on communicating design concepts to their teammates. They expect other people to just analyze their code and the perfection of their "design" will be self-evident. When other people point out design alternatives, they get impatient and cranky, because they've become emotionally attached to their BeautifulCode. 

See also ThreeStarProgrammer