Our ancestors had to struggle so much. Feudalism. Arranged marriages. Being expected to interact with people on public transit.

In general, I would as soon talk to and make eye contact with the people on the bus with me about as willingly as I would be manhandled by drunk lemurs. I’m sure they feel the same way about me. In the age before smartphones, your only option was to bring a book (advantage: no eye contact!) or a Walkman (advantage: can’t hear you!) with you, or to mutter ominously to yourself in such a way as to discourage people from approaching you. All these approaches had their advantages, although the problem with most of them was that in general people were pretty good about ignoring you, and it was just the people you really wanted to avoid who were oblivious to all your cues that you wished to be left alone.

And then came the smartphone. Stick headphones in it, and you’re done. You can play games. You can read. You can pretend to play games and read. You need never look up.

I began writing this on my cell phone, and I am pleased to note that as I strode boldly along, typing with my thumbs, I careened into an elevator shaft, accidentally crossed a picket line and totally missed several big warning signs that my friends were going through rough times and could use a sympathetic ear. Walking into traffic? That’s for pikers. I just fell into a manhole. It was amazing. I Instagrammed it. I know this phone far, far better than the back of my hand, which I last glanced at in passing in spring 2006. Friends and family have changed their hair, changed their faces and taken to striding around in the buff, and I have only noticed when people captured them in these activities and tagged them on Facebook.

I know, in theory, that this kind of distraction is dangerous, just as I know, in theory, that you should not text and drive, even at stoplights, even at that one really long stoplight where it’s totally fine and the person behind you is sure to honk and wake you up. But now, according to investigators in California, this has gone from theory to practice.

So I should have expected that this would happen. There’s a price you pay for being able to absent yourself from any room you’re in. When you carry a square in your pocket to whisk yourself off to a handy elsewhere where the company is more enjoyable, the scenery is better and the only obnoxious people vying for your attention are ones you already know and love, sometimes you forget that there can be an urgent reason for staying where and when you are.

As described by Vivian Ho, in SFGate.com

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.

They warned us about this. This is every terrifying thing you worried you might be missing out on with your eyes stuck on the screen. Experts are urging people to raise their gaze, likening phones to cigarettes — a bad habit we’re due to break. A few decades ago, no respectable person on a street corner was without one. But now the only people you see with them are misguided teens, the occasional leather-jacketed grandma, and those people in ads for e-cigarettes, and they’re certainly not welcome on public transit.

This is the danger — you want to be somewhere other than where you are. And your phone can whisk you away until you almost think you’re off this bus or train or out of this traffic. But you aren’t. You’re here. You might as well look up.