But it's definitely not an oxymoron to say that some brilliant coders can go down rabbit holes at the expense of their own (and company's) time and productivity. They may spend lots of time reading white papers, improving a design/implementation/test-suite beyond what is required, etc. It's just these coders don't place a high value on being as efficient as possible from a PM's perspective, but might be able to solve a problem 10x as difficult as the guy who is closing his tickets within hours of assignment.