A coworker sent me a link to The Parable of the Two Programmers. In my experience, there's a lot of truth in it.
Once upon a time, unbeknownst to each other, the "Automated Accounting Applications Association" and the "Consolidated Computerized Capital Corporation" decided that they needed the identical program to perform a certain service.
Automated hired a programmer-analyst, Alan, to solve their problem.
Meanwhile, Consolidated decided to ask a newly hired entry-level programmer, Charles, to tackle the job, to see if he was as good as he pretended.