Asking someone what they do for a living
In some countries, this is seen as offensive, as different jobs indicate different levels of salary and education. It’s the equivalent of asking how much someone earns.
Eating everything on your plate
In Asian cultures, this is seen as rude as it implies that the host did not give you enough food. They will most likely continue to fill your plate if you eat it all.
Entering someone’s home with your shoes on
In Japan, this is seen as disrespecting a person’s home if you keep your shoes on. Make sure you wear clean socks too, to save yourself the embarrassment!
While it’s customary to do it here in the States, in countries such as Japan, it is seen as offensive, implying a need for cash.