What Price for Digital Efficiency? NEW YORK - My parents are more tech-savvy than many people's. My mother was trying out albums on CDNow long before it was fashionable. There is almost no problem that my father cannot solve with a color-coded spreadsheet. But when we spend time together in cities, my usage of technology - to help us eat, entertain ourselves and get from here to there - can cause my mother to exclaim, "I don't understand this world anymore!" When I step back from my routines, I can imagine how strange the digitally enabled city might seem. A few finger swipes across a phone screen, and takeout dinner appears at your door - with no cash changing hands, nor even a signature. Another few swipes, and a taxi pulls up right next to you - and somehow it's automatically paid, too. I can walk up to cars in cities where I do not live, press my wallet to the windshield, and drive around for a while. No matter where I am, I know where faraway friends are, too. I can advise my mother on what to order at restaurants where I've never eaten. New York is a place of many frictions: the waits for taxis and trains and buses; the small kitchens that drive you to eat out; the tiny shops whose high rents are passed into the price of your shampoo. The farther you live from rarefied Manhattan, and the lower down the income ladder, the more frictions you know. But the technology world - which rarely senses a problem to which it is does not feel itself, coincidentally, the solution - wants to strip the city of its frictions. A growing crop of wares offers to help you smooth and "optimize" your experience of the city. And they are addictively compelling. It is hard to resist what makes life smoother. But there may be a case for skepticism of the urban hackers, whose streamlined and efficient vision for the city can at times seem more rightly projected onto a piece of code than a messy, chaotic, vital metropolis. This tension between the efficiency of a city and its chaos is reflected in the big splash that Tony Hsieh, the C.E.O. of the online shoe bazaar Zappos, is making in Las Vegas. Mr. Hsieh has acquired a great deal of land in a once-forlorn neighborhood called Downtown, and is redeveloping it as a 20-something's urban paradise: lots of cafes and boutiques, lots of strolling rather than driving, lots of the spontaneous collisions that in Mr. Hsieh's view define cities and give them their explosive creativity. He has invented a metric that he calls "collisionable hours" to measure how well his neighborhood induces people to get out of their homes and put themselves among neighbors. And yet the fortune with which Mr. Hsieh is remaking Downtown was made building Zappos, which sells shoes online and thus gives people one less reason to leave their house, mingle with others on buses and sidewalks and interact face to face in a shop. A lot of things that make cities worth inhabiting are inefficient. This is the tightrope that Mr. Hsieh walks: In business, his pursuit of efficiency keeps us shopping from home; in his service project, he is asking us to open the door, come outside and meander. If you live in a city and are a somewhat early adopter of technologies, you will recognize this tightrope. Every day you might find yourself wondering which inefficiencies should be eradicated and which savored, which problems hacked and which embraced. Apps like Seamless, in New York and beyond, make it easier than ever to have meals delivered to your doorstep with a few taps of a phone screen. "Only your food should be hot and sticky," the company's summer ad campaign says. FreshDirect is doing the same with groceries. In sparing you the stickiness and the toil, they also spare you walks through your neighborhood, meals at the nearest diner, many of the chance collisions that Mr. Hsieh so believes in. But the technology is compelling, because it reduces the irritations of city life. If you have the right apps, it is hard to have a bad meal in New York anymore. Everything is copiously citizen-reviewed, down to what dish you should order and which bartender pours the most generously. It saves time and money to know these things. It also removes a lot of the pleasure of discovery. New York is full of waiting. Perhaps in the future we won't have to put up with that, either. The transit authorities have already released an app that tells you when exactly the subway will arrive, to spare you having to wait with those weird people for too long. Even competitive taxi-hailing, that iconic New York activity, may be doomed. Apps like Uber and Hailo let you order a yellow cab from the comfort of your home or a restaurant, pop out at the last moment and swish into your car like a veritable rock star. I wonder when - or if - the dwellers of this city and others will begin to miss the old inefficiencies. Maybe they won't, much as people don't mourn horse carriages. Or maybe the city grows so smoothed that it starts to feel like another kind of place. Maybe it ceases to be a place where you joust with a blue-haired woman for a taxi at 3 a.m., where you strike up a chat waiting for the train, where you have a guy who sells you your fish, where occasional bad meals underscore the thrill of the great ones. What happens if we build cities so frictionless, so winnable, that we don't enjoy playing their game? Join an online conversation at http://anand.ly and follow on Twitter.com/anandwrites