There are a few reasons why people use small talk. The most obvious is to break an uncomfortable silence. Another reason, however, is simply to fill time. That is why it is so common to make small talk when you are waiting for something. Some people make small talk in order to be polite. You may not feel like chatting with anyone at a party, but it is rude to just sit in a corner by yourself. After being introduced to someone new, you probably don't know much about this person. So to show a polite interest, you have to start with some small talk.