Should You Zig? Or Zag?

Ed Hausafus in Eagle Creek, Oregon, writes:

Every week, my wife picks up the trash along our road. At the end there’s a mile-long hill. I offered to drive her to the top of the hill so she could walk down zigzagging across the street, picking up from both sides on the way down. It would be easier to pick up trash going downhill and shorter in the long run because she could do both sides of the road at the same time. Plus, shorter as she wouldn’t have to walk back up the hill, picking up from the other side. She disagreed, saying it was shorter if she walked down picking up from one side and then picked up from the other side on the way back up. I say she’s cuckoo bird. Who’s right? It’s a standard-width two-lane country road. A dinner rides on your answer.

Marilyn responds:

I hope you’re a good cook. I think your wife is right, mainly because all that zigzagging across the road is wasted time and effort. (She’s not picking up trash there.) Also, an outsider could reasonably say you’re the one who’s cuckoo bird for disagreeing with a wife who’s picking up trash along the road!