Because each human being is unique and irreplaceable, has a unique angle of approach to the world, as well as things in common with others, taking the ends and acts of others into account requires sympathy. If all human beings were basically the same, we could understand others simply by understanding ourselves. This requires generosity or open-mindedness. The common good does not require that individuals suppress their individual interests, only that they adjust their actions so as to be compatible with and to promote the development of the capacities of others. In other words, individual growth means widening and expanding of one's horizons to include others and their concerns.
Growth means deepening of character while extending and expanding the horizons of one's concern.
The common good includes cooperation as promoting individual growth and enlargment and broadening of individual interests to include the interests of others. The big picture includes others. Interdependence is a fact. We are connected. Being connected, we can work together or work against one another.