A friend of mine recently took his teenage daughter on vacation to San Francisco, where he'd once lived but she'd never been. As they drove to the tourist mecca of Fisherman's Wharf, he made a few detours, taking in some of the old sights to brighten his fading memories. Every time he departed from the route Google Maps offered, though, he noticed that his daughter grew anxious. He pondered her reactions and realized then that when they were driving in a strange place, she normally saw her parents dutifully following the directions offered up by the app. Disobeying it in what were to her unfamiliar surroundings clearly made her uncomfortable.