I've driven motorcycles, motorbikes, and automobiles for over 13 years over here...Thailand, Laos, Cambodia, Japan and Vietnam...
Vietnamese are well known for their driving habits around the world.
As to their 'bike' driving and can pretty much agree with you in part, but that still does not erase their inability to understand and comply with 'road rules'! As to their auto driving in car, bus or truck...you could make a TV show on their driving and parking...
I've driven flat-beds down an alley and backwards sometimes as well in the North East...inches, not feet.
Have a nice one and enjoy the coming summer. Hopefully another 1,200 to 1,800 km trip this year again...godspeed and fair winds.