The belief system of Keller Williams Realty International is the WI4C2TS.  The W stands for “Win-Win or No Deal.”  It is my favorite tenet of all, and let me tell you why.
I once knew an agent who took no prisoners.  She so zealously represented her clients that she often alienated the other agent, the other party (be they buyers or sellers), and sometimes even the home inspector, paralegal, lender, and closing attorney!  Her clients loved her for it yet rarely got much of a warm fuzzy at closing (or anytime throughout the transaction for that matter) due to the way she perpetuated an adversarial dynamic.  Other agents dreaded working with her because they had heard stories of how difficult she could be.  Local lenders and attorneys stayed on edge with her as they knew she gave no grace.
That same agent (her name is Amanda, by the way) now truly believes and embraces the concept that we are all in this together, working towards the same goal.  The goal is a successful closing, with both parties feeling they were represented professionally and competently.  Buyers like to feel they are making a sound investment, and sellers enjoy being able to move on with their lives. She sees younger and/or newer agents behaving as she once did, and she so badly wants to take them aside for some one on one time and let them know “it doesn’t have to be this way.”  Teamwork really does make the dream work.  You can 100% represent your clients to the fullest extent yet still treat others with respect, professionalism,  and dignity.  
I had a closing recently where the list agent (that same Amanda) was able to assist some precious sellers who had recently been dealt a tragic blow in their family.  I could not ease their pain… all I could do was see to it that things ran as smoothly as possible to give them as little headache as possible.  The other agent was a dear with which to work — her communication was excellent, and she was always prompt and efficient.  The buyer, whom I met when leaving my part of the closing, was giddy with delight at the thought of closing on her first home.  No one was anxious about running into anyone involved in the transaction — smiles and handshakes were had all around. Both parties were thrilled with their agents and felt their best interests had been protected.  
That, my friends, is a “Win-Win”!