I’m a 46 year old French man, and thanks to my family and travels I’ve tasted a variety of mayonnaises, all across the spectrum and a lot of the industrial stuff just tastes awful. They add so many preservatives in order to make it shelf stable, it completely loses any hint of the original flavour.

You can make fresh mayo with an egg yellow, some oil, a dash of vinegar / lemon juice (something acidic, really) and some mustard. Mostly you beat it until you’ve the desired texture and that’s about it! Even just this, you’ll have people arguing endlessly about which oil, which acid, which mustard, which proportions, etc :,D

Hellmann’s isn’t completely terrible, mind you. I was mostly being facetious with my remark.
It was the usual stuff you’d get in Ireland when I lived there, and it was okay. But there were much tastier brands available. And when I’m in France, even industrial brands, we have much better alternatives :P

I reckon Vietnam must have the same issue as we had in China : it’s too damn hot! And since real mayo is uncooked egg yellow it’s super bad to keep it at room temperature for too long. I never bought any while living there, because it wasn’t in my shops and I just adapt to whatever people eat locally, but sometimes when I ordered pizza they would have “mayo” sprinkled on top and although it was delicious, the fact it was sweet makes me think it had nothing to do with the original stuff :P