Traveling internationally from the US is a major trip in a way that it's just not in the EU.
From Edinburgh, you can reach 9 foreign countries in 1000 km: Norway, Sweden, Denmark, Germany, Belgium, Netherlands, Luxembourg, France, and Ireland. That's on the edge of Europe! If you're in Vienna, it's a whopping 31: Denmark, Sweden, Latvia, Lithuania, Belarus, Poland, Ukraine, Russia, Moldavia, Bulgaria, Greece, Italy, France, Belgium, Netherlands, Luxembourg, Germany, Czechia, Switzerland, Slovakia, Monaco, San Marino, Vatican City, Slovenia, Croatia, Northern Macedonia, Montenegro, Serbia, Bosnia, Kosovo, and Hungary, with Turkey and the UK juuuust out of reach.
From the US, if you live in Miami, a whopping four countries are within 1000 km: Cuba, Bahamas, Jamaica, and the UK (via its offshore islands). For most of the US, it's just one--either Canada or Mexico. Only if you're in Puerto Rico can you access a large number of countries in a short distance, and that's mostly because almost every Antilles island is a different independent country.
Or another way of putting it, in the distance it takes to get from the third largest city in the US (Chicago) to the largest (New York), it is hard to find a straight line in even the largest European countries that keeps you in the country!