There are things we do without thinking. For one, flushing the toilet. People usually don’t expect specific instructions before carrying out this relatively simple task.
If a user has to stop and think, the usability as we know it has gone down the toilet.
A well designed usability is one that lets us do things with least amount of thinking, one that requires minimal or no instructions. If a user has to stop and think, the usability as we know it has gone down the toilet.
So think really hard before using phrases like:
“Do not click the back button”
“Click submit only once”
“Use the button over there to do some stuff here…”
or “Do this and count to 5…”