We all believe we're right all the time. Sometimes we're not. Designers need to know how to say "no" to clients in the right circumstances. So then we have to understand what the correct circumstances are and what the final result is.
The team speaks about how to gain the trust of the client, build their confidence in design and be treated like an expert. And an expert knows when to say "no" and dig in heels and when to back down and look at the longer strategy.