I had some code that I figured had a concurrency bug in it, but I wasn't sure.
I pasted it to GPT4, said "I think this code has a concurrency issue, can you find it for me?" and sure enough, it told me what line of code was causing the issue.
It is also great for doing things that I don't do often. For example, I almost never write bash scripts (like once or twice a year). Now days I just use gpt4 to write the script for me. For example a couple days ago I needed to walk through a folder full of files and pass them one by one into another program, and if that call was successful, append the processed file to a list of files that had been successfully processed. Trivial, but again, I never write bash scripts. GPT4 had it up and running in a few seconds.
I can throw a file at GPT4 and ask it to create mocks for my objects so I can go ahead and start writing unit tests.
Awhile back I had setup a new express server, but after I added my CORS config everything stopped working. I spent an hour debugging, no luck. I asked GPT4 what the issue was, and it noticed I had defined CORS on the wrong line (after I had started my server up). Oops.
GPT4 is also great at coming up with sample command line options for utilities. Sometimes good examples in man pages exist, sometimes they don't.
Honestly, I don't use GPT4 as much as I should!