No matter how law abiding you think you are, the police can arrest you at any time because there is almost certainly some "crime" you have committed.
The vast majority of adult Americans have violated criminal law at some point in their lives. But whether you get hauled into court or not depends more on the discretion of law enforcement than any law. And it is difficult or impossible for ordinary people to keep track of all the laws they are subject to and to live a normal life without running afoul of at least some of them.
Source: The Case Against Overcriminalization - Foundation for Economic Education