When your API throws an error, what's the best way to tell people what went wrong using HTTP status codes?

hey everyone, let's talk about handling API errors. we usually see a bunch of 4xx and 5xx codes, but it doesn't always feel consistent, you know? what do you all usually do to decide which HTTP status code matches a specific error? and are there any unusual codes you find super helpful for showing API problems, like, beyond just basic client or server screw-ups