You cannot teach what you do not know.
Singaporeans are decended from the Chinese peasants, and they
have rather poor ettiquette, to say the least.
Hence they pass down their own ways- spitting, black face,
selfishness, stinginess, lack of manners.
This can only be overcome by a huge influx of people who have
good manners. Otherwise putting posters of the side of buses is
useless since one of the things Singaporeans, especially the
olderones, do, is ignore that sort of tripe. Besides, what's the
point of telling people to behave better, without some incentive,
instruction, or fear of punishment?
What kind of shit are you descended from?