Not every Vietnamese person litters, but my goodness, too many do. Those who don't need to start taking it upon themselves to say something to those who do. Seriously, it pisses me off in Hanoi when people throw trash on the ground but it really really really pisses me off when people throw trash on the beach or in a park or forest. I have no doubt that Quan Lan had perfectly clean beaches a year ago before tourism started to pick up there. However, now there's trash everywhere.
It's vile how on every beach there's a line of garbage and debris that is washed up with the tide.
Check out this photo:
I've finally come to this conclusion: If you want clean beaches don't come to Vietnam. Thailand is a hop, skip and jump from here and the beaches there are exponentially cleaner. Come to Vietnam for the culture and the food and the people (except the ones who litter) -- not for clean beaches. I'm officially done with Vietnamese beaches.