The mystery was solved when I noticed a letter carrier emptying a mailbox. I was slightly unnerved: Was the mail being stolen? He then went over to another mailbox with the flag up, and emptied that box, too. I got my hint when he skipped the mailbox with the flag down.

Yes, I was told, in the United States, mail gets picked up from your house, six days a week, free of charge.

I told my friends in Turkey about all this. They shook their heads in disbelief, wondering how easily I had been recruited as a C.I.A. agent, saying implausibly flattering things about my new country. The United States in the world’s imagination is a place of risk taking and ruthless competition, not one of reliable public services.

I bit my tongue and did not tell my already suspicious friends that the country was also dotted with libraries that provided books to all patrons free of charge. They wouldn’t believe me anyway since I hadn’t believed it myself. My first time in a library in the United States was very brief: I walked in, looked around, and ran right back out in a panic, certain that I had accidentally used the wrong entrance. Surely, these open stacks full of books were reserved for staff only. I was used to libraries being rare, and their few books inaccessible. To this day, my heart races a bit in a library.

Over the years, I’ve come to appreciate the link between infrastructure, innovation — and even ruthless competition. Much of our modern economy thrives here because you can order things online and expect them to be delivered. There are major private delivery services, too, but the United States Postal Service is often better equipped to make it to certain destinations. In fact, Internet sellers, and even private carriers, often use the U.S.P.S. as their delivery mechanism to addresses outside densely populated cities.

Almost every aspect of the most innovative parts of the United States, from cutting-edge medical research to its technology scene, thrives on publicly funded infrastructure. The post office is struggling these days, in some ways because of how much people rely on the web to do much of what they used to turn to the post office for. But the Internet is a testament to infrastructure, too: It exists partly because the National Science Foundation funded much of the research that makes it possible. Even some of the Internet’s biggest companies, like Google, got a start from N.S.F.-funded research.

Infrastructure is often the least-appreciated part of what makes a country strong, and what makes innovation take flight. From my spot in line at the post office, I see a country that does both well; not a country that emphasizes one at the expense of the other.