Just as a muscle needs to be challenged and given attention to grow; so does any relationship- In both the professional and personal life. It is true that muscle growth is not experienced until it works through fatigue; and it is when it is broken down that it builds itself up. It is through fatigue and stress that a muscle grows; both in size and strength.
It takes weekly, if not bi-weekly workouts for any body part to increase in muscle mass.
The same is true for a relationship with a boss or employee; with a boyfriend or girlfriend- with a friend, or roommate, or neighbor.
Too often we throw in the towel after one or two disagreements, a rough patch, or a bad mood...it will inevitably happen with every relationship in our lives. It is up to each of us to work through the fatigue...push through the stress, and experience growth.