As someone who has already lived in a couple of different countries, I have noticed VERY QUICKLY how Thais are STRONGLY ADDICTED to sugar, ALREADY AT VERY YOUNG AGE!
As if they got addicted already in mum's womb!
Compared to other cuisines, I find Thai food amazingly sweet, be it noodle soup, fried rice, salad,...
I have asked Thais, whether it traditionally has always been the case, and if so, whether they have always been using refined sugar - knowing that it is quite a recent invention in human history -, or whether they were using natural sweetener such as mango-based things... Nobody could give me any answer.
I have never been to Burma yet, but I have a Burmese co-worker who recently arrived in Thailand: while she is thankful for having the opportunity to escape her country's situation and to come to Thailand, the very first thing she "complained" about, was how sweet Thai food is! Her Burmese friends told her even before she arrived to buy cooking material, since she would not stand more than a couple of days eating outside!
But guess what: when we all have lunch together with the team, one of my Thai co-worker always feel the need to pour sugar in the already sweet meal! Exactly like the French who, like as a reflex, add salt in the already salty meal!