I had the same problem the other day watching the new Bond film.3 girls were sitting behind me talking thru the whole movie. I snapped and turned around and said in a loud voice, "Are you going to talk thru the whole movie because it's pretty flucking rude. You aren't in your living room."
Well that shut them up.
Some lady a few seats away said "thank you".
Unfortunately my blood was boiling and I couldn't focus back on the movie
That's the problem right there. The satisfaction of getting someone to stop their inappropriate behavior is never as much fun as the satisfaction of just being able to enjoy the theater experience in peace. It only takes a few minutes of chattering or a few too many kicks to the back of the chair to pull my mind out of the movie screen and into the theater seats, if that makes sense.