Personally, GPT-4 has wasted about as much of my time as it's saved with its constant hallucinations and lack of insight when writing NixOS derivations and a Rust web backend. I wouldn't let it near my delicate-hackish checkpointing work in C++.
What are you doing where it serves you well?
Regular Expressions. I hate doing regexps. It is excellent at them.
Wiki articles for an encyclopedia I'm developing. It is great at this, but occasionally I catch it hallucinating articles out of whole cloth because it has access to zero information about what I asked it about, so it just goes from the article title and imagines what it must be about.
I know where to use it right, and I've found my output has not only doubled since I started using it, I am enjoying coding even more than ever because it has got rid of the worst drudgery that would cause me to switch from my IDE to my browser and bring up HN to avoid working.