Relationships are built on trust and respect.
Agencies, if your client doesn’t respect and value the power of advertising, your expertise and knowledge of their business, how can they trust you with their brand?
Conversely, if you don’t respect your client’s expertise and their belief in the power of advertising, how can you trust them with your brand?
Look at the best, longest, most fruitful client-agency relationships and you will no doubt find mutual trust and respect at the core.
Both are earned, by the way.