There is only one thing about GPT that is mysterious: what parts of the model don't match a pattern we expect to be meaningful? What patterns did GPT find that we were not already hoping it would find?

And that's the least exciting possible mystery: any surprise behavior is categorized by us as a failure. If GPT's model has boundaries that don't make sense to us, we consider them noise. They are not useful behavior, and our goal is to minimize them.