Marx saw work, the effort by humans to transform the environment for their needs, as a fundamental feature of human kind. Capitalism, in which the product of the worker's labour is taken from them and sold at market rather than being part of the worker's life, is therefore alienating to the worker. Additionally, the worker is compelled by various means (some nicer than others) to work harder, faster and for longer hours. While this is happening, the employer is constantly trying to save on labour costs by paying the workers less and figuring out how to use cheaper equipment. This allows the employer to extract the largest amount of work and therefore potential wealth from their workers. The fundamental nature of capitalist society is no different from that of slave society, in that one small group of society exploits the larger group.