This one hits home. Not my home, but some of the people I go out with.
Here is a surprise to you. These people have no manners. I know a few friends, that will bury themselves in their phone. Facebook updates are more important than face to face friend updates.
The only time I consider taking out a phone is due to a conversation that I have at dinner that needs clarification. Whether it's a trivia nonsense or results to the game or results to the horse races.
I know people that will take pictures of their food, for god knows what reason. Then after they finish their meal, they will play with the leftovers. They are a ball at buffets, because if they don't like what they eat, they will make an extra mess with the food they don't eat just to make a point I guess. When someone comes to clean a plate from the desk, they are preoccupied on their phone and will not even look up, and give the wave of the hand to the peasants that serve them.
And no matter what comment you make to them, unless it shows up on their facebook page, they are oblivious to what you say.