The "Just Say No" engineer is a person who knows what existing tools can do, while more junior people don't know what their tools can do. So junior people are constantly proposing new types of yak shaving (new architecture, new storage backend, new framework, etc) that must be done before solving the problem at hand. This is all wasted resources and time, even if LLMs let you shave yaks faster. A good JSNE focuses your resources on solving problems straight away, not pouring them all into a bottomless pit of busy work.