Surapon,+1 ... on several occasions in the far east when I did something that was not culturally correct, I was only corrected in private while no one was around or looking, and that too very politely. But I still remember a woman from a "developed" country, (while I was buying some Christmas deco) told me that I would never be invited at her house with that deco ... I didn't even know the lady and there were 5 people between her and me at the billing counter (where I was paying for the deco), yet she felt the need to "express her feelings" at the top of her voice about some items a random guy was buying ... I wanted to tell her that "in my house, we welcome everyone for Christmas" but I just smiled and left.
Do whatever you feel comfortable with. When I lived in Thailand I really struggled with the language, I just don't get tonal based languages, and I am very sure I was most inappropriate on many occasions, however even when I was nobody ever corrected me in public. It is a shame we failed to extend the same courtesy.
But you are amongst friends and you are most welcome to treat us as such.