Sometimes the best way to avoid interacting with anyone is pretending to interact with someone else. Some might consider such a ruse dishonest or impolite, but navigating public spaces isn’t always easy — especially if the space in question is crowded and you’d rather not be bothered. It can also be a useful way of removing yourself from unwanted encounters with strangers who might make you uncomfortable. (Preventing these encounters in the first place is why some people wear headphones when they’re out and about.) If you ever need to do it, just make sure your fake conversation sounds convincing.