Experience has taught me that advertisers get the best results when they pay their agency a flat fee. It is unrealistic to expect your agency to be impartial when its vested interest lies wholly in the direction of increasing your commissionable advertising.
David OgilvyThe worst fault a salesman can commit is to be a bore. Foster any attempt to talk about other things; the longer you stay the better you get to know the prospect, and the more you will be trusted.
David Ogilvy