The Design of Everyday Thingsby Parker on TwosTake people’s difficulties as signifiers of where the product can be improved.Eliminate all error messages from electronic or computer systems. Instead, provide help and guidance.Allow people to continue with their task: Don’t impede progress—help make it smooth and continuous. Never make people start over.Think positively, for yourself and for the people you interact with.Human error usually is a result of poor design: it should be called system error.