Nice is relative, in places where everyone is nice - no one is nice i.e. the bar is super high for your actions to be considered nice. On the other hand, if you are in a society where everyone else sucks and is 'bad' all the time then any decent thing you do is considered nice.
to be nice is to act to ppl as the as u want em to be, being nice has not exact definition, some guy would buy u a new car, and the other could only give u a beautiful rod, both of em are nice, just do as much as u can and don't wait to get paid..