The worst is when it can't do something right, and it does a horrible mock/hack to get it "working." I had a claude fake benchmark data, that pissed me off a bit, though I did make a major architectural improvement to a tool as result (though the real benchmark would have probably made me do it anyhow) so it wasn't all horrible.

this happens to me constantly, it's such a huge waste of time. I'm not convinced any of these tools actually save time. It's all a fucking slot machine and Gell-Mann Amnesia and at the end, you often have nothing that works.

I spent like two hours yesterday dicking with aider to make a one line change and it hallucinated an invalid input for the only possible parameter and I wound up using the docs the old fashioned way and doing the task in about two minutes

The mistake was using AI for a two minute fix. It totally helps at some tasks. Takes some failures to realize that it does indeed have flaws.