Is it offensive to say "Thanks" to someone in that person's language?
I am Chinese and work in my parent's Chinese restaurant but I have been heavily "Americanized" as I grew up in a small town. I went to school here and barely speak a lick of Mandarin or Cantonese.
The other day, I was waiting on an old couple and their son. There happened to be some unrelated Chinese people dining there that night. The lady asked me if they were part of my family after she sat down, to which I replied no. Then she kept saying thanks to me in Mandarin as I served her and her family throughout the night. Later she told me that my English is pretty good, haha.
Personally, I don't get offended very easily and was amused that this person was making assumptions based on how I look and where I work. Maybe she says "Gracias" instead of "thanks" at Spanish restaurants as well.
I wonder: Do people consider this to be an attempt to be polite and friendly in that person's language or a presumptuous way of showing off their knowledge of one word of another language?