Whether you are insisting that introspection is only ever accurate by coincidence, or just that whatever accuracy it possesses is of no practical utility, neither position bears much relationship to reality.

[You are factually incorrect.] We've tried developing models of human psychology by relying on introspection - it was in fact the first approach taken in the modern age. Most researchers abandoned it soon after it became clear that our experience of our cognition did not in fact permit useful models to be generated. We've had more than a hundred and fifty years, and that approach has not been the least bit fruitful.

The introspective modalities, however it is that they are best characterized, have the same quality - partial reliability - that you attributed to the external senses

No, our senses are much more consistent, both in themselves and with the properties of the world that we interact with regularly, than our self-awareness.

and everyone uses them every day to get things done

[No.] I have no idea where you picked up the belief that our cognitive self-reflection is an important part of our decision-making, but it has very little to do with reality.

[Last warning before I start deleting posts again, Caledonian. Kick the habit. -- ESY.]