Most people are apprehensive when they go to Vietnam, especially Americans to whom the country is not exactly an American Idol of a travel destination as desirable as the singing competition.
Their anxiety is understandable as Americans dropped more bombs in Vietnam during the Vietnam war than in the whole of World War 2! Imagine you are now going back to your former enemy's territory.
For others, well, Vietnam is a communist country so will they be harrassed by the secret police? Or worse, thrown into jail on trumped up charges. Don't laugh...people have expressed such fears to me.
To be honest with you, I too had a stab of anxiety the first time I travelled to Vietnam.