Cursing is compulsory, while belching is optional.
In Japan, especially where I live--in the sticks with Buddhas, talking on the train is considered a very big no-no. Whispering's OK. Cell phones are damned. Fondling strangers is ignored. Heck there are bars -or were bars in Tokyo that looked like the inside of trains where fondling is/was the reason patrons frequent/ed the joint. :D