Rob Pike's Rules of Programming (1989)
> Rule 1. You can't tell where a program is going to spend its time. Bottlenecks occur in surprising places, so don't try to second guess and put in a speed hack until you've proven that's where the bottleneck is.I wish people would follow this rule and just let stuff work.  I recently encountered the most extreme version of this I've ever seen in my career:  a design review where a guy proposed a Redis caching layer and a complex custom lookup scheme for a Can't we just let stuff work?  I'm no fan of MySQL, but can't we admit that a ubiquitous and battle-tested piece of technology, applied to a canonical use case, on tiny data under near-ideal circumstances, is probably going to work just fine?  At least give it a chance before you spend days designing and documenting a bunch of fancy tricks to save MySQL from being crushed under a few megabytes of data.