Which countries are the most US friendly for tourisM?
There are many countries around the world that are friendly to tourists from the United States. Here are a few examples:

1. Canada - With its close proximity and shared language, Canada is a popular destination for US tourists. Visitors can explore vibrant cities like Toronto and Vancouver, and take in stunning natural landscapes like Banff National Park.
2. Mexico - Mexico offers US tourists a diverse range of experiences, from stunning beaches to vibrant cities and ancient ruins. Many parts of the country are easily accessible from the US by car, making it a convenient destination.
3. Australia - Although it is a long flight from the US, Australia is a popular destination for US tourists. Visitors can explore cities like Sydney and Melbourne, as well as the country's stunning natural landscapes like the Great Barrier Reef.
4. United Kingdom - The United Kingdom is another popular destination for US tourists, with London being a top draw. Visitors can also explore historic sites like Stonehenge, or take in the stunning landscapes of the Scottish Highlands.
5. Japan - Japan is a fascinating destination for US tourists, offering a unique blend of traditional and modern culture. Visitors can explore bustling cities like Tokyo and Kyoto, or immerse themselves in traditional Japanese culture by visiting temples and hot springs.
What would be the least friendly?
The least-friendly countries for US tourists include a number of countries that have hostile relations with the United States, or have ongoing military conflicts within their borders.

Governments frequently arrest and imprison American tourists:
 - Iran
 - North Korea
 - Russia

Ongoing warfare or government collapse:
 - Libya
 - Ukraine
 - Somalia
 - Haiti
 - Syria

For US tourists, it is worth checking the United States Department of State's Bureau of Consular Affairs, the government bureau that creates and updates travel advisories, for the most recent news on a country before traveling there.