Paul's weakness is that he doesn't understand the dangers of gambling. However, Paul is lucky not to live to the age of seventy as moaning over the loss of his money is going to be really painful. A person cannot always win in life. Paul started gambling as there is always a chanting of "There must be more money." Paul tries his luck on gambling, only to find himself addicted to it.
Both 'Green' and 'Paper' show gambling. However, stocks can be predictable and carry some type of logic while gambling is by pure luck. Both carry the person addicted to it deeper and deeper into the hole. The more you lose, the more you try to win it back and lose even more, eventually causing you to be bankrupt.
Ah Boh, like the "blind man", does not spend the money on the basic necessities of life, such as taking care of her mother and buying food. Instea, she spends her money on buying lotteries, and gets nothing in return. The same can be said about the "blind man". He spents his money on lotteries, instead of a sandwich, a cup of hot milk tea or some paper and ink. After he bets on the nimber 13(unlucky number), he cannot concentrate on his work, thinking about 13 all the time.
Could the blind man also be a metaphor for gambling. After all, there is blind luck involved and no one can see into the future!