In most languages, a greeting is usually followed by "small talk". Small talk means the little things we talk about at start of a conversation. In English-speaking countries people often make small talk about the weather: "Nice day, isn't it?" But there is something special about small talk. It must be about something which both people have the same opinion about. The purpose of small talk is to let both people agree on something. This makes meeting people easier and more comfortable. People usually agree about the weather, so it is a safer topic for small talk. But people often disagree about religion or politics so these are not suitable topics for small talk in English. The topics for small talk also depend on where the conversation is taking place. At football matches, people make small talk about the game they are watching: "Great game, isn't it?" At bus stops, people may comment about the transport system: "The bus service is terrible, isn't it?" Greetings and small talk are important parts of conversation in any language. The way people greet each other and the things they talk about, however, may be different from one language to another. This shows that there is much more to learn when we learn a language than just the vocabulary and the grammar of the language. We also have to learn the social behavior of the people who speak it. Why do people need small talk?
To choose a topic for conversation. To agree about the weather. To let meeting people become easier and more comfortable. To learn a language.