One of the moments where I thought cell phone use was slightly inappropriate was when I observed a man and woman dining together and each of them was eating and talking on their phone simultaneously.

I thought it was funny that typically two people dining together talk to each other but in this case they were each being rude to each other, rude to the service staff, rude to the diners on either side of them and rude to the people on the other end of the line. I know, I don't actually know what they were talking about, they could have been very important Saturday night phone calls and it's none of my business. NPR might say it's just "a sign of the times."