I often use AI successfully, but in a few cases I had, it was bad. That was when I didn't even know the end goal and regularly switched the fundamental assumptions that the LLM tried to build up.
One case was a simulation where I wanted to see some specific property in the convergence behavior, but I had no idea how it would get there in the dynamics of the simulation or how it should behave when perturbed.
So the LLM tried many fundamentally different approaches and when I had something that specifically did not work it immediately switched approaches.
Next time I get to work on this (toy) problem I will let it implement some of them, fully parametrize them and let me have a go with it. There is a concrete goal and I can play around myself to see if my specific convergence criterium is even possible.