I think you should at least mention province you were visiting since people behavior is really different depend if how close the place to usual tourist routes. I spent just 3 months in Vietnam and didn't traveled that much, but there is huge difference in people reaction to foreigners.

In the South as soon as I moved away to the places that tourists rarely visit I always get attention from all sort of people because you can literally be the only European guy who was around in past week. Also I was surprised how many kids of school age have a good English skills.

In same time in SGN nobody ever spent time on me with no reason.