Of course there's always a degree of margin to everything, nothing should be absolute.
I agree though about considering the general mood of the surroundings, if majority of the people are lively and happy perhaps due to a celebration or a holiday then that's totally fine, but if people seem to be tired and want to rest inside the train or a bus due to exhaustion after a day's work, then better be mindful of our noice.
As for smoking in non-designated areas where children and non-smokers usually pass by is still a no-no for me.
Thank you for sharing your opinion ^^