The rule
Use error messages to offer a path forward and success messages to confirm progress.
Why it matters
Error messages stop a process, making user motivation fragile; they must be helpful "first aid" to prevent abandonment. Success messages provide certainty and instruct the user on the next mandatory step. Both message types are opportunities to build a relationship by reacting to user actions according to social norms.
How to apply it
- Explain what happened simply, provide a specific remedy, and never blame the user.
- Be specific about what was achieved (e.g., "Account details saved") and explain what happens next.
- Use active voice to clarify who performed the action.
- Avoid technical jargon and error codes in the main message body.
Example
Before and after
Weak
"The transaction was completed successfully."
Stronger
"You've sent $50 to Anny."
Tensions and exceptions
Humor can lighten the mood in error messages but should be avoided if the brand voice is conservative or if the error is high-stakes, such as a failed payment or medical record issue. Clarity must always come before being clever.