The only justifiable stopping place for for the expansion of altruism is the point at which all whose welfare can be affected by our actions are included within the circle of altruism. This means that all beings with the capacity to feel pleasure or pain should be included; we can improve their welfare by increasing their pleasures and diminishing their pains.
I would say that Barack Obama not only made me a better person but made me better at my job. He's one of the most intellectually curious people you'll ever meet and really brings that out in other people.