W-O-M

Positive word-of-mouth (W-O-M) about your business is more powerful than any advertising that you can buy. You can spend all your marketing dollars on full color ads, commercials, infomercials and direct mail and it's still not as forceful as one person telling a friend or relative to consider your business.

The person passing the good will may have had a pleasant experience or feel that they received a great deal so they want to let everyone else know about it; it's just human nature. The people who got the W-O-M passed on to them know it's sincere and was not from the company but from someone they trust. You just can't buy that kind of praise or referral because it's not for sale, you have to earn it.
More on W-O-M in chapter 8 in "The Jelly Bean Principle" avail at Amazon, Kindle or signed copies 877-700-1322