Every agency knows how long a client report takes to build. Almost none know how long the client spends reading it. In this talk, Harry shares what his team has learned from instrumenting hundreds of paid-media reports after the "send" button, how many people actually open them, how long they stay, which metrics they look for and when, and why the data practitioners hunt for on their own dashboards is so rarely the data they put in front of clients. This is about knowing what they really care about.