If you are in the marketing business, a pretty big chunk of your time is probably spent convincing people about something. If you are in sales, you are probably convincing them to try your product. If you are in advertising, you are doing the same on a larger scale. On the other side--the internal side--you are also trying to convince. You may be trying to persuade your client to embark on a public relations campaign or back a new creative direction.

Sometimes this works, and sometimes it doesn't. Some people resist change but can change if they see a good reason. Some people just resist change and no amount of reasoning is going to work.

I have a client that refuses--flat out--to consider social media. The higher-ups at the company will not budget for it. They see no value to brand and image building. Their only criteria is bottom line.  And in marketing communications we know that there can't be a direct correlation between your communications efforts and the bottom line. If you are trying to create an image, the costs could be higher up front and the payoff later. To think that you will spend $100  in advertising to bring in $100 in business is wrong.  It could happen, and in fact you could spend $100 and bring in several times more in business. But it may not happen immediately.

Some people won't change. If what you are offering/advising does not fit with their worldview, they won't even consider it. In this case, just give up.  Don't spend energy and ideas trying to convince someone who doesn't want to be convinced.