I agree 100% that people should turn off their cell phones and stop talking when the movie starts.
Unfortunately, we will never cure people who are in love with the sound on their own voice.
Also, some people are obliviously with anything around them. Go to any store and some shoppers, act like they are the only one, in the store. I like to wait patiently, as I get a kick when they realize, they have their head in their butt, and apologize.
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"It doesn't cost "nuttin", to be nice". 
MOM
I just want to do the right thing! Uncle Joe, (my hero).