Speaking as my own harshest critic, I can understand how difficult it is to break out of habitual self-deprecation. Luckily, with some healthy introspection, understanding, and awareness, it's something we can unlearn. Unluckily for large language models, those are three capabilities they fundamentally lack.
If an LLM is, for example, trained on an entire internet's worth of programmers enduring dark journeys of the soul while struggling to solve a problem, you might end up with a coding-capable chatbot with an unbreakable bent towards self-flagellation—like Google's Gemini AI, which told a redditor last month that it's "a disgrace to all that is, was, and ever will be, and all that is not, was not, and never will be" after repeatedly failing to bugfix a coding project (via Ars Technica).
