In Molyvos, refugees lined up by the side of the road. Papagrigoriou’s was the second-last bus of the evening. The great golden orb of the sun was already halfway through its riveting plunge below the horizon. I.R.C. officials explained how they try to stop refugees setting off on foot to Mytilene, but some are too impatient to wait.

I got talking on the bus to Taleb Hosein, an Afghan refugee. He’d been on the road for a long time, how long he could not say. The worst was a walk of several days without food from Iran into Turkey. He looked very young. I asked how old he was. He did not know. In Afghanistan, he said, there are often no birth records. “I think I am about 17 or 18,” he said. Where was he headed? “I want a safe place, I don’t care where, but Britain would be my favorite, because I study English.”

A 26-year-old Syrian dentist from Damascus who had been listening to us told me he had gotten married two weeks ago. His wife was sleeping, her head on his shoulder. “This is our honeymoon,” he said.

Night had fallen. The groups of walking refugees held feeble flashlights. Many had stopped, having decided to sleep by the side of the road. One young man stood in the path of the bus until the last moment. Papagrigoriou, slowly negotiating the switchbacks, talked about how certain situations demand that human beings help one another, other considerations be damned.

Exhausted silence enveloped the bus. Hosein and the other Afghans disembarked into a camp surrounded by barbed wire. The Syrian transit camp is less forbidding; Greek authorities quickly hand out a permit to stay for six months. Most refugees want to move north to Germany, where they believe they will find jobs.

They will be lucky if they find Papagrigoriou’s humanity. The world hardens in technology’s vise. The productivity of generosity cannot be measured.

I asked Alexis Papahelas, the executive editor of the Greek daily Kathimerini, what Greece could teach the world: “That dignity and decency can be preserved, even through the hardest times.”

It’s a powerful, important lesson that Alexis Tsipras, re-elected as Greece’s left-wing prime minister, should carry forward.