It can save your life. Or someone else's. saysuncle.com:
I was once walking through Costco pushing a loaded buggy that had a large box across the top that put it about head high. Some 20 something kid staring at his phone and walking is walking right toward me. I could have said “hey, moron, pay attention”. I didn’t. I just stopped. And watched the kid walk head first into it. He looked embarrassed, then apologized. I said to him something to the effect of “life is easier if you pay attention”. So, get your head out of your phones:
A man standing on a crowded Muni train pulls out a .45-caliber pistol.
He raises the gun, pointing it across the aisle, before tucking it back against his side. He draws it out several more times, once using the hand holding the gun to wipe his nose. Dozens of passengers stand and sit just feet away – but none reacts.
Their eyes, focused on smartphones and tablets, don’t lift until the gunman fires a bullet into the back of a San Francisco State student getting off the train.
Situational awareness is not just for gun nuts.