How much more does it cost to find and develop a new customer than to keep an existing one?   The numbers vary, depending on who measured it, but probably five times is a reasonable estimate. 

Implication: your existing customers  will, very likely, come back for more. Even better, they may make referrals of others who then become customers, and who then refer more, and so on.

But things work the other way, too: if you antagonize a customer, you not only lose their business  now and in the future (and have to spend five times the effort to replace him), but you also may find that not only are there are there no referrals, but may even be a lot of negative referrals.

The existing customer you antagonize costs you a chain of prospects that you never know about. (Not to count those prospects who happen to talk to that one-satisfied customer who is satisfied no longer.)

But suppose you are arrogant and suicidal and want to go about turning off happy customers. What are the best methods?  We'll take for granted that they were happy because you did a good job for them first time— you showed up on time (or made delivery when promised), and so forth.

Partial checklist for turning happy customers into ones who'll never do business with you again:

1.  Don't show up on time. (Cable Guys are you listening?)

2.  Don't return calls.

3.   Don't follow through.

Case: Ed the Tile Man came to us highly recommended by people in an up-scale community nearby. Mr A referred him to Ms B and so on.  We took the advice. Ed came and did an estimate, and it sounded good. The work took several hours longer than he'd estimated, but he kept to his estimate.  And, before I go on, let me say that 99% of the job was perfect. An A, though not quite A+.

A couple of weeks later, some small problems developed and we called him. ("5 year warranty" written into the contract.)  No call back. Another call, same result.  Meanwhile, we began hearing that the people in the next community who'd recommended him were having the same experience. Ed the Friendly Tile Man has turned into Ed the Invisible Man.

Now we've all quit dropping calls into his answering unit; we all just wrote him off.  Well, not exactly: we've spread the word.  So now Ed has to move on to some place new and find another chain of new prospects, and so forth.

I'm not alone in this, I find.  Everyone knows Seth Godin, right?  He did a post a couple of days ago, "The $20,000 phone call" See the article in Seth Godin's blog on another aspect of this same issue: when a prospect makes that first call (perhaps with $20K opportunities in hand), and that first phone call is not answered, or answered by some snotty-voiced unhappy receptionist.  First impressions matter: and they may be the end of the story.

And another of my favorite bloggers, Jonathan Fields (like this humble blogger a lawyer who moved on to better things!), in his  post Business Strategy Fail: Save $300, Lose $20,000 also focuses on the little things that (a) turn off existing customers, and (b) project indifference to those who would be prospects, and (c) wouldn't take much effort or cost many dollars to fix, and make everybody happy.