Vietnam is currently a developing country, and many things had taken a part in developing it into what it is today. These things range from French imperialism to China's influence over Vietnam for many centuries. Many people have their own takes and have their own reactions on what Vietnamese culture is like. Vietnamese culture is a combination of many foreign sources that came together and matured into something unique.
The Vietnamese language was written down in the form of Chinese characters in the beginning as early as 100 B.C. and lasted up to the 19th century when the French colonized Vietnam and banned its usage. At this point in time was the creation of the Vietnamese alphabet, which used the letters of what we use everyday. In modern times, you can still see Chinese characters in some Vietnamese print but it is mainly made up of the Latin alphabet with its own unique tone marks and pronunciation ( for example the letter "d" is actually pronounced with the same "y" in yam). The influence of both of these sources still stick today, as the major religion in Vietnam a combination of Buddhism, Confucianism, and Taoism and after that is Catholicism. The formal attire of the Vietnamese people was also adopted from China, but slightly branched off in its own way as years passed and the result was the áo dài, most commonly worn by women.
Everyone enjoys Vietnamese food, but one of its greatest characteristics is the main usage of little oil, many vegetables, foundation of rice, soy, or fish sauce, and freshness. Here in America, the soup base often has MSG within it, but not as much in Vietnam. The usages of such ingredients create a good balance in diet, as long as not too much hoisin sauce or sriracha is added. The most common dish known is probably either Phở or Bún bò Huế and these are known for a reason as they're also quite popular in Vietnam. But don't be mistaken as there are plenty of other noodle dishes and rice dishes, rather there is just too many to count! Fun fact: in Vietnam, there are plenty of family owned shops that sell this dish, and if you were to translate the currency of an American dollar to a Vietnamese Dong, it would cost you about 25 cents for a bowl.
My experience in Vietnam was centered in the city of Saigon. In Saigon, the main source of transportation were motorcycles and taxis. The amount of cars (excluding taxis) was a ratio about 1:50 if I remember correctly ( it could have been more ). The first floors of many homes were made into shops that sold a variety of things from snacks to home equipment like brooms, sandals, and dishes. On the sidewalks were movable carts that sold sugarcane drinks, food, or other things. Sugarcane drink is very well-known in Vietnam, aka as nước mía. The carts that sold them had a pile of sugar cane so that the drink would be freshly made in addition with some lime for flavor. In terms of religion, once or twice a year my family would go to a Buddhist temple in order to give respect to the dead (my grandparents). Even in my home are multiple shrines, one that is taller than 7 foot tall and about 5 foot wide whereas the other 2 is about the size of half an adult's upper body and burning incense is natural. Sandals were worn everywhere, inside and outside but shoes weren't allowed inside similar to other Asian families. Truthfully, I do not know all the rules and manners in Vietnam, but I do understand the complexity of the history of Vietnam. Hopefully you also found this information interesting!