Error Messages Should Blame the System, Not the User

Compare: "Invalid input. Error 422." vs "Hmm, that card number looks short — mind double-checking?"

The first blames the user and offers nothing. The second takes responsibility ("hmm"), names the specific problem, and suggests a fix. Same error, completely different emotional outcome.

The bite: Write every error message as if you're standing next to the user, slightly embarrassed on behalf of your own product. Because you should be.