"How are you?" is a nice question. It's a friendly way that people greet each other, but when a person says "How are you?" he expects to hear the answer "1," even if the person's friend isn't fine. The reason is that “How are you?” isn't really a question, and "fine" isn't really a (n) 2. They are 3 ways of saying "Hello" and "Hi".
Sometimes people also don't say 4 what they mean. For example, when someone asks, "Do you agree?" the other person may be thinking: "No, I don't agree. I think you are 5." But it doesn't sound very polite, so he may say, "I'm not so sure." It's a 6 way to say that you don't agree with someone.
People also don't say directly what they are thinking. For example, when a person wants to 7 talking with other people on the phone, he 8 say "Let's stop now", sometimes he will gives a (n) 9 instead, "Someone is at the door", "Something is burning" so on. The excuse may be real, or it may not. It's a polite way to stop a 10 and it doesn't hurt the other person's feeling. It's an important way that people try to be nice to each other, and it's a part of the game of language.