Amdahl's Law is one of my favorite things from college. It's general principle, optimize the largest parts of a project for the biggest impact, is applicable across more than just programming. I've used it to help prioritize tasks within projects, both professional and personal, that have little-to-nothing to do with programming, and decide where to optimize project costs.

Cool for the perspective, but also subsumed by the concept of returns to scale (that entails diminishing returns and includes constant and increasing returns to scale). ie- rediscovery of microeconomics

[dead]