We all have personal interests, and in the vast majority of cases, those interests must compete. In the past, such competitions were resolved with blood, and although things haven't changed much today, other visions emerge to develop a richer and more complete world in every sense. One of those visions is egoistic altruism, such that if other people grow economically and socially, it's likely that through that growth you can get what you want.
At first, the global economy was regulated by the net yield of agriculture. Although there were other elements of considerable value (metals, weapons, textiles, etc.), the main source of wealth was food production. The fixed size of land destined for cultivation inevitably limited production. From a certain point of view, one could say the system was in equilibrium, but with the introduction of new factors (starting with population growth), the most direct route to keep growing was at someone else's expense. That leads us to the long list of wars, conquests, looting, and "colonizations" that humanity has carried out in its history. If the size of the pie didn't change, the conclusion was a single one: The best neighbor we could have worked for us, or was dead.
Hundreds of years later, the Industrial Revolution kicked the door and everything changed. Machines took over the heaviest work (which also had its dark side), and food production multiplied, causing a "contagion effect" in other industries. Today we can say we are enjoying its benefits, with access to safe food and water, protection from the weather, energy, transport, health, and education. But the world didn't sit back. Innovation entered the equation, developing solutions for classic problems, and even anticipating others that may arise in the near future. And there's the key: You really want those problems to disappear. Why? Because it's what benefits you most personally.
For example: There are still children working in the fields. Maybe you think you can't do anything about it, but that situation doesn't serve you. Ideally, those children would access a robust education, which in turn will enable the path to careers that will lead them to industries where they can create new resources for you, and for them. Your personal benefit, your "selfishness" so to speak, doesn't need more child labor: It needs doctors, engineers, architects, programmers, artists. People who do better, with new ideas that multiply innovation, associated with specific demands that we will all be willing to pay for, making the market bigger, and optimizing our quality of life.
