I think there may be a common misconception that with a US passport, Americans can freely enter and leave a country at will. Although this is mostly the case, there are numerous countries where a visa is needed prior to arrival or can be obtained upon arrival. Anyone hoping to do any type of travel overseas should definitely do their research in terms of obtaining the proper visas via the State Department.
The countries I’ve visited that do require a visa have had options to obtain a visa on arrival. However, those can be time consuming and somewhat confusing if you’re new to the country. I’ve also heard that bribes are somewhat common. Obviously, thousands of people are able to travel to these countries every year so it can be done. For me, I choose to take care of all the necessary paperwork before leaving the US for two reasons. Mainly, if there were any problems in obtaining the proper paperwork, I can change my travel plans before I leave and no time is wasted. Also, without knowing when the airport is at it’s busiest with arrivals, getting through customs could be a nightmare if not prepared.
If you’re going to be backpacking around the world, planning ahead may not be a real viable option. However, if you’re like me, I like being able to travel with less stress and taking care of potential problems before I leave really helps.