There is one good reason for this, he is holding the purse strings.
However, in advertising post-production there may be up to 20 people in the room with you and, in effect, they are all gods. Even though you are all working on the same commercial, everyone has a different opinion because everyone has a different agenda.
The creatives want to win an award so they can get a bonus.
The account manager wants to keep the client happy without upsetting the creatives.
The TV producer wants to keep the creatives happy without upsetting the client.
The director wants to make a break into Hollywood.
The producer is desperate to keep within the budget.
The editor wants to be a commercials director.
The client wants to increase the sales.
And you?
You just want to keep everyone happy.