Sounds like you got a real
Vietnamese coffee. All kidding aside, my experience drinking coffee here (Vietnam) is that most of the coffee shops have bad coffee. I am not sure if it's the beans, the machines or the culture. There is, maybe, 1 in 7 coffeeshop that will do the coffee kinda okay. I don't think the locals care too much (basing on google reviews).
Either way, I'll take this over any other SEA or Asian country where it's a hassle to find coffee outside metro hotspots. Cafes and Coffee here is available everywhere and usually within a 30 seconds walk.