[dexwiz]

That seems to be my experience. Sometimes it gives great answers, sometimes terrible, but it rarely gives any indication between the two.

[Sharlin]

That seems to be largely an effect of its training. I'm pretty sure that OpenAI has just biased it to be too helpful, leading it to confabulate answers. If you specifically prompt it to tell you when it doesn't know, or isn't sure, it should fare quite a bit better. Also, GPT-4 is a huge improvement.