Forgiveness

Users like to explore an interface and often learn by trial and error; however they expect to have immediate success with the majority of attempted tasks. An effective interface allows for interactive discovery. It provides only appropriate sets of choices and warns users about potential situations where they could damage the system or make global changes to the system.

Even in the best-designed interface, users can make mistakes. These mistakes can be both physical (accidentally pointing to the wrong command or data) and mental (making a wrong decision about which command or data to select). An effective interface avoids situations that are likely to result in errors. It also accommodates potential user errors and makes it easy for the user to recover.