One thing that I learned when doing raw API LLM usage is how drastically the results can vary call per call with exactly the same input. I think that on average, people using agents underestimate the variation in results from a given turn command are, and so overindex on "X technique worked well" or "if I do Y then this will happen" or even "it did Z task well last time so it will this time too" or "{Model} is great at {thing}"