Yearly reports. They can be buggy, can be off by millions, due to rounding errors. They can crash. They can run for days. Nobody cares enough to rewrite them, b

Yearly reports. They can be buggy, can be off by millions, due to rounding errors. They can crash. They can run for days. Nobody cares enough to rewrite them, because regulation will change before that effort amortizes. Also note that I wrote "code" originally, because there can be programs which are run very often, but certain code paths are not, so my statement applies even for some parts of popular software. The image I think would be valuable for you to consider is a curve, where 20% of code has 80% of all executions, and 80% of code get's the rest. It makes sense to put in a lot of effort into writing the top 20%, but on any given day it is very likely you'll be working on the lower 80%.