Learners of Japanese have a tendency to use ください to ask other people to do something, because in classroom, teachers always ask students to do things by saying ‘書いてください’ (Please write), ‘読んでください’ (Please read), ‘座ってください’ (Please sit down), etc. It is not surprising that students may think when they ask somebody to do something, they should imitate their teachers and use ください. This, however, is a very serious mistake one can learn in classroom or textbook.
How come it can be wrong!? Our Japanese teachers are native speakers. They simply can’t be wrong. Wait. Wait. Wait. I didn’t say your teachers were wrong. I said that it was wrong for you to imitate your teachers. Let me explain to you in details.
If you have read my other article “The biggest mistake in textbooks”, you should know that the Japanese change their wordings when their social status changes. So if your teachers use ください as a teacher, you should not just imitate the phrase without keeping the social status as a teacher, i.e. if you are not a teacher, you can’t use ください the way your teachers use.
If you are not a teacher, then don't talk like one.
Many dictionaries explain that ください is a polite way to ask somebody to do something, but in fact sentences ending with ください are orders, because listeners are not given the choice to say yes or no. By using ください, you are just TELLING somebody to do something politely. You are not asking. You tell. You tell your boss to do something. You tell your customers to do something. Do you think you boss and customers will be happy talking to you? An order is an order, no matter how polite it is. When your teachers use ください to tell you to write, read and stand up, they are correct because, as your teachers, they have the right to order you to do such things.
That said, there are situations where it is alright to use ください when you are speaking to your boss, customers or people you need to pay respect. For instance, you can use お座りください to tell them to sit down or 召し上がってください to tell them to eat. Because in these two situations, you are GIVING your service by showing people their seats and serving people their food. It is alright for you to give polite instructions because you are doing people a favor, not asking for one. (BTW, お…ください is a politer form of ください and 召し上がる is the honorific form of 食べる.)
ください is okay if you are giving a service, not asking for a favor.
However, when you ask the same people to do something FOR you, e.g. lend you a book or sign a recommendation letter for you, you can’t just use ください. It is not right even if you use お…ください or other polite forms, because you are asking, not giving. The same goes for English as well. When we ask for a favor, normally we don’t just say ‘Please lend me some money’. Instead, we ask questions like ‘Could you lend me some money?’ By asking questions, the listeners feel that they have a choice to say no and thus are not offended by your request. In Japanese, you should also ask questions when you ask for a favor. When you ask people to lend you a book, you should ask ‘本を貸してくださいませんか’ (Can’t you lend me your book?), or use ‘本を貸していただけませんでしょうか’ to make it even politer.
Make your request a question so that listeners feel less offended.
You may think that it is safe to forget about ください once and for all and use くださいませんか from now on. Sorry, you can’t do that. The question form くださいませんか should only be used when you are asking for a favor. If you use this form when giving a service, it will sound like ‘Why don’t you sit down now?’ in English and make people unhappy.