A lot of people think Ad agencies are designed to do marketing for companies. That the goal is to drive success for their clients. That their success as a business, is built on doing a good job.

None of this is true, for the vast majority of ad agencies in the world.  Most ad agencies are not focused not to deliver good results.  Most ad agencies are not focused on building a business for you  Most ad agencies are not focused making your company successful  As somebody that spent millions and millions and millions of dollars as a supervisor and heading up ad agencies for years, let me give you the real secret behind with an ad agency is actually supposed to do.  Most ad agencies number one and only objective, is to make the person that hired them, look good to their boss.  There are obviously exceptions, but these exceptions are far far far outnumbered by myopic investment bankers who sell ideas, ego and spend far too much time writing reports and making presentations than actually sitting in the work.