I've traveled to 25 countries and everyone wanted to ask - or tell - me the same things about the US

One of the most confusing aspects of American culture is the tipping system.

Americans are used to tipping a wide range of service professionals, from bartenders and waiters to hairstylists and airport shuttle drivers. On top of that, Americans tend to tip in greater amounts than people in other countries, where a 10% tip or simply rounding up to the nearest dollar amount may be more commonplace.

Meanwhile, there are plenty of countries where people don't tip at all. It's usually people from those places who have the most questions and criticisms of the US system.

Any traveler who's been to a US restaurant has probably encountered the infamous American portion size. The massive dishes sold at most eateries come as a shock to most non-Americans, especially if they come from countries where taking home your leftovers isn't the norm.

The average American eats dinner around 6:20 p.m., and anything between 5 p.m. and 7:30 p.m. is usually considered a standard mealtime.

That time frame is laughably early for people in certain other countries. In Argentina or Spain, it's not uncommon for dinner to start after 11 p.m.

One quirk that always makes an impression on non-Americans is how in the US, sales tax is not factored into prices, and is instead added on at the cash register.

There are plenty of theories of why the US differs from the rest of the world in that respect, and the issue was a favorite to discuss among non-Americans I met.

The US has more cars per capita than almost every country in the world — only San Marino has more — with more than 900 cars per 1,000 Americans.

On top of that, more than 90% of Americans drive their cars to work, and the number of American car drivers is still rising.

Americans have a reputation abroad for being patriotic — sometimes to an obnoxious degree.

That's not to say people around the world don't love their countries. But I did encounter plenty of curiosity about the American tendency to display flags and proclaim the US the greatest country on earth.

American gun culture is surprising and difficult to comprehend for people in practically every country I traveled to.

The US easily leads the world in both gun ownership and gun-related deaths, and gun control became a frequent topic of conversation in countries where accessing a firearm is virtually impossible.

The United States jails a greater percentage of its population than any other country — around 700 out of every 100,000 Americans is behind bars, according to the Prison Policy Initiative.

That's around five times greater than the rate in most other countries, and it's not easy to provide a good explanation to people who ask why.

One of the most common misconceptions I encountered abroad is that all Americans are wealthy, and some people assume that the typical American has multiple cars and a big house.

It's true that the average American's income is higher than the global average, and the US has more billionaires than any other country. But many people abroad were surprised to learn that wealth wasn't the norm for most Americans, and the the US suffers from income inequality and poverty, too.

For many people around the world, the only exposure they get to the United States is through Hollywood movies.

That often leads to a warped perception of American life in which young people are wholly devoted to drinking and partying.

I must have let them down when I told them most people I know in the US are focused on work, paying rent, and getting enough sleep.

American food gets a bad rap in other countries — mostly, I suspect, because of widespread American exports like McDonald's and KFC.

Some people I encountered abroad disputed the idea that aside from those fast food offerings, there was even such a thing as "American food" to begin with.

My typical response was to rattle off examples of regional US favorites, such as southern barbecue, New England clam chowder, or Cajun gumbo.

American beer has the same reputation abroad as American food — terrible.

But just like with food, non-Americans may be forming their opinions of American beer solely off the country's mass-produced exports — nearly half of all Budweiser sales are made outside the US.

Those attitudes may be changing, as American craft beers are becoming increasingly popular in Europe and other beer-loving regions.

Americans are known for being some of the most monolingual people in the world.

In reality, the stereotype doesn't hold up: Americans, and especially young ones, are becoming increasingly able to communicate in languages besides English. (Part of the reason Americans are known as monolingual is because the government isn't asking the right questions about our language use.)

It may come as an even bigger surprise that 10% of working-age Americans — that's 19 million people — don't speak fluent English.

The US is the third-largest country in the world by area, but it's sometimes hard to comprehend how geographically imposing America is until you go there yourself.

Whenever the subject came up, I was ready with some fun facts to illustrate the vastness of the US. Like how it takes more than 30 hours of non-stop driving to traverse the entire East Coast, or how a flight from Seattle to Miami takes upwards of seven hours. And how the largest US state, Alaska, is big enough to be the 17th largest country in the world.

Another thing that surprises some non-Americans about the US is its diversity. Between TV, movies, and the news, it is easy for someone abroad to get the impression that the US is uniformly white and Christian, so it can come as a surprise that this group represents less than half the country, according to a recent survey.

A big source of confusion I came across was the relationship between the 50 states and the US government.

Many non-Americans were surprised to learn how much autonomy each state has, like when it comes to setting its minimum driving age, selling alcohol, or legalizing marijuana.

It's natural for people to associate the United States with its leader, but many non-Americans assume that the president is loved and supported by the majority of the country. At this point, it would be harder to find someone who does support him, according to recent polls.