When these landscapers got a referral from one customer to another, they had to explain some important caveats. Unfortunately for the landscapers, these clients were not happy with the deal they were going to get. Referrals are really important to many companies. In recent years, there's even a big incentive by lots of brands to tell your friends about their product. How many times have you gotten a friend to sign up for a random product just so you can get a discount? Or, if you're crafty, you…