Alan Cooper

to minimize mouse movement

The intervention should not, however, be in the form of a standard modal error message box that stops the action and adds insult to injury, but rather through careful visual and textual feedback that lets you know that you are messaging a group rather than a person, or that you haven’t enclosed any attachments even though you mentioned that you were.

restart the application

particularly on the web

The user then clicks

something is lost in the process

This flexibility usually is absent from automated systems.

It is one of the first casualties when

By allowing many small, temporary mistakes into the system and entrusting humans to correct them before they cause problems downstream, we can avoid much bigger, more permanent mistakes

These inflexible rules make the human and the software adversaries.