In my personal opinion based on years of writing apps that generate error messages, a good error message is "one that stops the *** user emailing me without bot

In my personal opinion based on years of writing apps that generate error messages, a good error message is "one that stops the *** user emailing me without bothering to actually read the message first". sadly I have failed in that respect, but it has kept me employed for a looong time, so not all bad ;)