The first reason to have an antagonism is the bourgeoisie's aim to acquire more profit. In agricultural societies, the landowners used their lands as a tool of getting wealth. They recruited peasents to cultivate their lands, took taxes from those peasants and usually gave them just enough amount coin and land to reproduce themselves. Today's industrial capitalists' tool to gain more wealth is essentially factory. They have the means of production (machines, production apparatus, and raw materials) and capitalists employ workers to produce goods for gaining more wealth. But in order to increase the profit, capitalist always tries to limit the expense. In that sense, owner of the factory gives the wage at the minimum level or forces workers to work long hours for same amount of money for producing more so as to increase their surpluses. The purpose of listed activities is to increase the income and limit the expense as much as possible. In other words, the capital is based on the exploitation of the working class. To avoid being cut the source of money, capital gives opium for masses with the different kinds of ways such as religion, art and state. Religion is usually used for legitimizing the position of owner and worker; and also State is the insurance of capital with police and law to prevent the poor rebellion against riches and State provides security of private property. As a consequence, the owners of the capital always try to minimize the expense and maximize the income for raising productivity with numerous ways. They use state, law and religion to legitimize their actions and keep the workers numb to avoid rebellions of any sort.
Necessity of the capital for the workers to continue their lives is the second reason of the aforementioned antagonism. Workers, who were once upon a time peasants, had to work in factories in order to maintain their lives after the dispossession of the land they once cultivated. They worked to barely survive because they had nothing but their labour to sell. While doing that they wanted to true value of their work. Marx said: "It was the labourers whose work actually produced the good by their skills and effort, so they had the right 'the full fruits of their labour' or another way to say, surplus." Workers were living and working in hard conditions (basic housing without bath or toilet, working 14 hours a day, and getting low wage). Proletariat was not aware that they were really a group of people sharing the same economic and social conditions because of the effort that came from capital in order not to wake them up. The shared experience and awareness of exploitation is the basis of unified class action, as Marx called it "class for itself", workers rised up against system. For instance, in the period of 1780-1850, there were food riots, hundreds of strikes and demonstration in industrial areas. Thousands of men and women set up clubs, joined trade unions, went on strike, demonstrated and signed petitions. Fear of the losing the source of the money was the key factor of workers who gained rights from the owners. Gradually, workers gained access to education, had certain hours and limited age to work from state and rarely from the owner as in the example of Robert Owen- he prohibited children under 10 to work, freeing women to work, ensuring each child an education and he instituted old-age and disability pensions. Consequently, workers resisted the system to get better living and working conditions after they realized that they were actually being numbed by the owners of the means of production.
To sum up, all the examples show us that the conflict between owners of the means of production and the labourers are inevitable due to their natural economic interrelationship but also they depend on each other. Capital needs labour to produce good for making profit while labourers need bourgeoisie to get money for reproducing themselves. This mutual antagonistic relationship has always been there in the history with different class names and probably will be there until it changes into a system in which the sources are equally distributed.