It's often much easier to begin a conversation — "Hello!" — than to gracefully end one. Anyone who ever sat on an airplane (or train or barstool) next to an over-friendly neighbor will understand. To the rescue: Joe Berkowitz. In a post on The Awl he writes, "Forcing a conversation into a half-nelson is a life skill that nobody should be without, like changing a tire or making a grilled cheese sandwich." For example, if you're stuck next to a friend of a friend of a friend at a bar:
All you need to do is introduce a third party into the mix, and the first time the other ends of this triangle complete an official back and forth, you're officially allowed to leave. As with the shopping situation, you only really have to endure this moment for as long as you feel the need to be polite. At any time really, you can start looking around as though you might have just spotted Judah Friedlander in the perimeter, and abruptly excuse yourself. Go to the bathroom for a while. Get a drink. Dance. You're free.
There's also advice for the truly risky airplane disengagement, and phone and Skype bailouts, among others.