Underpromise and Overdeliver (?)

The whole premise of under-promising and over-delivering is to make sure that you actually DO deliver. Seems like it's the wrong thing for the right reason.  Leaders who under-promise set expectations low or at least less than.  It's better to set expectations high and then establish methods and systems that do their best to guarantee success.

Besides, as a direct report, if my boss doesn't set expectations very high, am I getting the message that he or she thinks I can't deliver or I don't have what it takes?  Hmm...