I’m at the base of a towering mountain. My tour guide stands before me, telling me about the beautiful lake 10 miles up the trail. It sounds perfect.

“I forgot my glasses, my compass, my map,” says the tour guide, “And I’ve also never been here before.”

Not so perfect.

Five miles in, the tour guide spots a cave and decides we’ll do some spelunking instead of continuing the hike.

“Well, the cave is here, and it seems like a shame to waste it,” the tour guide says. “And some people really like spel...