I'm a Carpet Cleaner but this applies to nearly every service, what the cowboy doesn't realise is that they are merely wrecking the reputation of the given service in its entirity. I have heard people say that they clean their own carpets now, because the last guy left them wet for 3 days and they could do a better job themselves. Well this is true, but unfortunately they aren't going to trust any carpet cleaner ever again, are they?
I used a cowboy builder once and to be honest, I don't trust any builder now..... So I know where the customer is coming from.