A lot of Americans participate in what is called small talk, where you make conversation with strangers or acquaintances about non-controversial topics, such as the weather, sports, or popular television shows. While waiting at a bus stop, in line at a store, or in an elevator, don’t be startled if a stranger says something to you like, “Did you watch the Super Bowl last night? What a game!” They might also make a joke about the long line you’re both in, or comment on the current situation. Small talk is supposed to be harmless, so it’s not okay if a stranger says something that makes you uncomfortable.
Some Americans detest small talk but they realize it’s part of the American culture to chat about harmless topics in order to establish a connection and to start building a friendship.
Source: Ten Things to Know About U.S. Culture