For all his roughness of birth in the novel 'Wuthering Heights' by Emily Bronte - Heathcliffe has the intelligence of the oppressed, the watchfulness of the exploited - he has learned like many mistreated individuals to be an opportunist. These people learn early in life that there is no love, no care and that the only person they have in the world to look out for them is themselves. This is sad but,for some people who become sociopathic, callous and cold as a result - inevitable. Apart from the love he thought Catherine had for him until even she mocked him - he has no love. He learned to watch for opportunities and sees a mega big one in Hindley. He sees his Achilles heel - the dissipating weakness which will empower and enrich himself. He watches the enemy drink and gamble his way to destitution - looking as if he is helping but in reality waiting for the final fatal moment to strike without mercy, winner taking all. Such is the nature of the beast - Heathcliffe!