HOW TO WRITE ERROR MESSAGES THAT ACTUALLY HELP USERS RATHER THAN FRUSTRATE THEM

Summary from the TLDR Web Dev newsletter

Effective error messages not only help users recover quickly, but also builds trust with them. However, the message content themselves are often overlooked in UX design. Instead of vague, robotic, or cutesy language, write conversationally in an active voice, clearly identify what went wrong, and provide specific next steps.