Saigon vs. Hanoi
There’s one true thing about Vietnam: Saigonese and Hanoians dislike each other. And they like to discuss this topic.

They hate the voice:
Saigonese don’t like the Hanoi voice. They think the accents are too much and that way of speaking makes Hanoians sound fake. They hate it when people in Hanoi stare at them every time they speak, as if they were aliens.
Hanoians don’t like the Saigon voice, either. If you speak the Saigon voice, prices will be up 2 or 3 times. They hate it when two Saigonese speak too fast because they don’t understand much, as if Saigonese didn’t speak Vietnamese.

They like to compare Saigon with Hanoi:
Saigonese are proud that they are friendlier and more easy-going than Hanoians. Unlike Hanoians, they mingle with other people quite well.
Hanoians are proud that Hanoi has so many lakes. And they laugh when they realized the so-called “Ho Con Rua” in Saigon is not a lake at all.

But they envy each other:
Saigonese think Hanoians are real players. But in fact, you see more lights and people outing around midnight in Ho Chi Minh City.
Hanoians think Saigonese are more fashionable. They don’t know a fact that Saigonese buy more at supermarkets than clothing stores.
Saigonese wanna visit Uncle Ho’s Mausoleum as often as Hanoians.
Hanoians wanna turn right like Saigonese do when the traffic light is red.

How they treat you:
Saigonese will never show that they hate you. But don’t think that they like you. If they don’t call you again, they mean that you’re not fun to hang out with.
Hanoians are famous for being acting “cool”. And when their compliments are so toneless, they might as well speak of the weather, but you should be very careful. They hate you.

If you’re a foreigner, it’s better for you not to compare Saigon with Hanoi when speaking with any Saigonese or Hanoian.