The three pictures are real life examples of catastrophic mistranslations, however funny it may be; it does not directly affect you. A mistranslated wait sign will at worst result in raised eyebrows, or a mistranslated subtitle can at worst render a poor cinema experience. However, this does not mean to say professional translators are not useful; in fact the opposite is true. The key is to know when to use a reputable translation company or to keep the job in house.
Imagine the scenario where you are trying to gain access to another country; you will need your personal documents translated. For countries with strict procedures and regulations, the last thing you would want is having your visa rejected due to someone mistranslating your forms! A translation agency will be the best choice for this situation.
When one single word can change the entire meaning of a document, to say you need to be careful is an understatement. When the documents to be translated are a patent or a user manual; would you leave these tasks to an amateur?
Of course, one major area where mistranslation can have disastrous results is legal translation. Poor translation in this aspect can cause significant financial and legal consequences. A translator will need to know the correct terminology, syntax, the law and good writing skills to have the best chance of providing a problem free legal translation service.
To conclude, knowing when to use professional help is the key decision to be made. To save costs, a menu translation may be translated in house by the restaurant staff (although there are many funny examples to show you on this also) however; important documents which cannot go wrong should be left to a professional translation company.