One of the concepts in economics that people seem to have difficulty grasping at an intuitive level is how other people’s income affects one’s own income. Many people instinctively ascribe to the “lump theory” of money, in which one may imagine all wealth to consist of a set amount of money, like a dragon’s hoard. If you capture more of it, that means that someone, somehow, has ended up with less.
In certain circumstances, this theory might describe things pretty well, but in most times and places wealth grows and shrinks with productivity. Basically, if I am able to produce more goods and services of value to othe people in the same amount of time, then my income grows.