Or a junior dev will see "Error 422: thing_id is required" and instead of updating the request they sent to include thing_id they'll report it as if it's a 500 Internal Server Error until you pick up the ticket and read the error message to them.

Of course, they didn't actually put the error message in the ticket, they'll write "backend crashed" and put a screenshot of the front-end crashing because they didn't do any error handling at all.