Banning the c-word ('client'), acting as one team, sharing data, incentives and pressure to perform are notable ingredients in a relationship now spanning 45 years. 

Though that tenure is exceptional, lessons can be learned. 

Those on the agency side know they are in the service business - that is the reality, but in the most effective, long lasting relationships, that isn't how they are treated. The beauty in a long term relationship is the trust and understanding that comes with the partnership. They are two-way dialogues. How can any client expect trust and good work if the agency is dangled on a string, with the threat of a review from day one?