Reality Principle
The ego has a tough job trying to satisfy the needs of the id without giving it everything it wants and engaging in inappropriate and unacceptable behaviors. The ego manages to satisfy the id without engaging in all sorts of inappropriate acts by following the reality principle--the guide directing our unacceptable sexual and aggressive urges to more acceptable targets. For example, when you walk down the street and see an extremely attractive person, the ego, working on the reality principle, helps us realize that it is not socially acceptable to cross the street, grab the person, and have sex with them. Instead, the ego follows the reality principle which tells us that there will be other, more appropriate people, places, and times to fulfill these needs.