Not sure if you tried this out on any other model, but I find that a lot of the tonal issues are pretty specific to ChatGPT. An untuned davinci-003 doesn't feel the same need to wrap things up happy every time, and produces much better imitations of style. There's still the usual LLM issues (slow divergence from whatever the prompt was, occasional loops, a sort of dreamy quality to every narrative), but ChatGPT always writes in the bland style of a corporate memo because it was deliberately retrained to do that.