Every one of the links he provides about how to write good user-facing error messaging mentions that the error text should spell out what went wrong and what th

Every one of the links he provides about how to write good user-facing error messaging mentions that the error text should spell out what went wrong and what the user can do to fix it. The problem with this advice is that in 2012, everything is on the web and problems either arise from network issues, database problems or bugs that can be patched into the live product in many cases. Therefore, the vast majority of users don't care what went wrong, largely because in most cases there's only one thing they can ever do to fix it: try again later. The example he uses to kick off his post - a GMail send failure - is a canonical example. Try again later. As for error messages being too casual, with the showing of sad faces and big, bright usage of words like "Oops!" - it's because you have about a fiftieth of a second to communicate to the user that something went wrong and they're seeing something that's not what they're supposed to be seeing. Literally, two words is too much; user study after user study has revealed that people simply don't read error messages and fruitlessly click "OK", either thinking there was no problem, or wondering if they did something wrong.