Difficult customers are never easy to please. Some of them can take complaining and anger to a whole new level.
Ask anyone you know who has been in sales or customer service and they will usually have a couple of stories to tell of having dealt with a variety of difficult customers:

The ones who find fault [...]

Who likes not his business, his business likes not him. – William Hazlitt
Love your business! I can’t stress this enough. Over the years, I have met some people who were passionate about what they were doing. Passionate about their business.
They did everything they could for their business. From staying up late at night to get [...]