Error pages for form-field validation are dreadful. You’ve just filled out 20 form fields, yet you get the same bloated page thrown back in your face because a single field failed to validate.
I clearly recall the often loud sighs of despair during our last usability study each time a test subject encountered a validation error page.
We also noticed that test subjects who had been exposed to validation errors began to take preventive actions to avoid them in subsequent steps, by writing things such as “N/A” in the “Company name” field if in doubt about whether the field was optional.
