A few years back, EWR to Bologna, early 20's gal behind me was chatting nonstop with her seatmate. This was long after the meal service had concluded and the cabin lights were dimmed as it was an overnight flight. When I'd had enough, I turned around and said, "This is an overnight flight. Can you please keep it down?" She replied with something about she has as much rights as me, and I said a bit more loudly: "I am traveling on business. When I land, I need to shower and go directly to a meeting. Therefore, I need to sleep as much as possible NOW. If you would be silent for a few seconds and listen, you would notice the rest of the plane is completely quiet. Take a hint."

With that, I turned back around and closed my eyes. She did finally shut up.