@PyRulez He can have multiple goals. Goals can have lots of cause and effect. For example, Greg learns to be funny, outgoing, and charismatic so he can get people to follow him. Then he will use his followers to create an army. So Greg would still care about people and be social, but only because it serves his long-term goal.
So he understands emotions and pretends to have them, all while having the cold logic of Sherlock or Spock. There is actually an episode of Sherlock on Netflix where he acts like he cares about someone and even proposes to them to get past security. It is genuine seeming enough that no one can tell he is fakeing.