[jiggawatts]

A great example of how such basic CS knowledge can save weeks or even months of time wasted was posted here on YC News: https://news.ycombinator.com/item?id=22459661#22460040

The OP proudly showed off a custom B-Tree implementation for a problem where a sorted array and binary search would be far simpler and much faster in practice.

Applying even a smidge more CS knowledge could have resulted in using Netwon's Iteration as the lookup, which is the almost perfectly optimal solution: just one random I/O to do a lookup even with a cold cache!