Some time back the venerable television was known as the "Boob Tube" in slang parlance and alluded to the belief that watching television excessively made you stupid. It appears that the smartphone is the new Boob Tube.
Everywhere you look peeps have their noses buried in their smartphones. The vast majority of those are walking around and not even paying attention to the world around them. Are you guilty of doing this? Go on. It's okay to say so. I won't tell anybody since I do it too :D