TV licence fee staff have been issued with a manual advising that customers who use the words "idiots", "shambles" or "useless" are likely to be making a complaint.
Other indications that a viewer may be unhappy include use of capital letters or the phrases, "When will you people listen?", "Who do you think you are?" and "Sort yourselves out!"
The document also reveals quirks in the rules about who needs a licence - the Queen, prisoners and diplomats do not, but all other Royals and prison officers who live in the grounds of a jail do.
The 964-page official handbook, which was released following a Freedom of Information request, sets out in detail how the fee should be administered.
A large section is dedicated to dealing with complaints, including prepared answers to regular objections about the BBC's "offensive" programmes and the aggressive tone of licence fee warning letters that could "shock" elderly people.
Staff are advised to look out for particular "keywords" suggesting a customer is protesting about some aspect of the £145.50-a-year fee.
These include: "compensation", "complaint", "disgraceful", "disgusted", "incompetent", "appalling", "furious", "intimidation", "mistakes", "harassment", "rude", "threatening", "outrageous", "upsetting", "unacceptable" and swear words.
The guide also lists warning phrases, such as "I am extremely angry", "I demand an apology", "lack of courtesy", "your failure" and "I will sue".
The document adds: "Remember underlining of key words and phrases or the use of bold or capital letters designed to make certain parts of a letter stand out is also an indication of a complaint."
Officials are given stock answers to common criticisms of the licence, including "The BBC is producing poor programmes, some are offensive, I am only going to pay a proportion of the fee" and "If an old person had received this letter they would have been very shocked".
The two main companies contracted by the BBC to administer the TV licence received 35,000 complaints in 2008 and 37,000 in 2009, according to the TV Licensing website.
The manual, known as the TV Licensing Ask Helpscript, discloses that the Queen is exempt from paying the fee but other members of the Royal Family are not.
Prisoners do not need a licence for TVs in their cells or other communal areas because prisons are subject to Crown exemption.
But a licence is required by prison officers who live in jail grounds and have a TV in their accommodation or for a staff social club on the premises.
The document also notes: "Diplomats enjoy immunity from prosecution. If they choose not to buy a TV licence, TV Licensing cannot enforce the law against them.
"Embassy buildings also have diplomatic protection and TV Licensing cannot enforce the law if the embassy chooses not to buy a TV licence."
The BBC Trust announced last month that the licence fee would be frozen at £145.50 for at least a year because of the financial pressures on viewers.
A TV Licensing spokeswoman said: "There are more than 25 million licences in force.
"In 2009-10 complaints totalled 29,900, representing 0.1% of all licence holders, which was a 16% decrease on the previous year.
"Complaint numbers are published each year in TV Licensing's annual review."
She added: "The Government is responsible for setting the level of the licence fee and defines who needs a licence."