> It's not like people are losing sleep because they don't know which code is side effecting I’m pretty sure many people are, since this will be a likely cause

> It's not like people are losing sleep because they don't know which code is side effecting I’m pretty sure many people are, since this will be a likely cause of them losing money in their businesses. They could be losing money directly, and they could be losing money as a consequence of having to invest more developer time in solving unexpected effectful behaviour. In fact, I can think of one comedic case where a programmer literally lost sleep because he programmed his garage door to respond to HTTP GET requests, instead of POST requests which are conceptually meant to be the ones that are effectful.