Why does Mr. White rescue the Monkeys Paw from the fire? Why don't the Whites heed Morris's warnings?

Mr. White suffers from the same greed that many of us do. Once he hears what the paw can do, he wants a piece of the dream. The White's desires transcend any of Morris's warnings.

We already know that Mr. White is impulsive based on his behavior in the chess game. We see him retrieve the Monkey's Paw because he thinks he is one of those people to whom it won't happen regardless of the warnings from the old fakir. He thinks his wishes are so slight that nothing bad could happen.