In my opinion, generally, vietnam is not a terrible place. Otherwise, it is very terrific and amazing with a lot of things to discover and experience.
It can be traffic. You can find it very difficult to cross the street or you can see some people break the rule like cross the red light. But if you live here a long time, you also find it easy. They can drive very fast but when they see you, they are skillful to not cause accident.
It can be food and drink. About Vietnamese food, i think nowhere in the world has diversity and delicious dishes like Vietnam.
It can be Vietnamese people. Although, they are quiet outdated, talkative, curious, they are really friendly, sociable, generous and so on with everyone, especially foreigners. Coming to Vietnam, you have feelings like at home, you will be welcomed like president :))).
It can be cultural tradition, education and so on. If you have not experienced yet, you could not understood deeply about Vietnam.