Promising the unbelievable before delivering on said promise will leave potential buyers knowing you are pumped up, arrogant, over confident and probably out of touch with reality. "Of course you will say that about your own product or service. That is expected."
Ears and then minds are more open when your raving fans are sharing with others: "I can't tell you how fabulous and amazing it is. Words do not describe it. You have to at least look at it. You'll see what I mean."
It doesn't take a rocket scientist to tell business owners to base their marketing plan on a multi-level marketing system (MLM) to create a company which has an extended army of "raving fans" with testimonials who reach out to the world. Promising the unbelievable is then narrowed to those who are already users and believers where the message is a continual support of their belief and thus leaves them validated. (Regardless of whether any of the MLM participants make a profit.)
Politics is another such example. "I can tell you that I am the greatest leader and I am the most trustworthy of the candidates." This will be put into the "outbox" as quickly as the public hears it and the response will be "yada-yada-leader-yada-yada-great". This is one reason why it is more beneficial for politicians to talk about the other guy vs. themselves. There is a higher chance of creating a response vs. "bragging".
Then came social media tools. Now people can share a testimonial with their eyes closed and a click. They can do it under almost any condition and with mobile in hand, they share their own version of "great" with anyone around the world. Social media tools are important because when it becomes habit to click and share, the job of marketing gets easier.
In the not so distant future grocery stores will have QR codes on the shelves next to specials where people can scan and share what they find via a mobile device. "Look what I found" in the brick and mortar will be the next version of sharing.
If you know for a fact that testimonials (raving fans) are beneficial to business, to getting dates, to winning over the boss... then why are you promising the moon and stars to people who will disregard what you are marketing/selling?
Why not instead give the moon and stars to people in need which will cause a reality change significant enough to improve their quality of life or business? If the results are amazing and unbelievable enough, they won't need prompting to share the news about their transformation. Word spreads simply because you have value and are trustworthy and those raving fans make the judgement call as to how "unbelievable" you might be.
Marketing by word of mouth is risky because you may not be able to deliver enough value to create raving fans. If that is the case, think again about your product, service and those you serve. Are you holding back? Are you basing success on transactions or relationships?
Marketing isn't restricted to what you say about yourself and your business. Don't sell the unbelievable... do the unbelievable. By doing so others will share their story about your products and services.