For the majority of people, the main reason why they are hard-working is because they want to gain money. Personally, I strongly agree with this view, as individuals nowadays are aiming to have a successful life and get a well-paid job.
To begin with, I believe that innumerable people are working hard because their goal is to obtain money for their bright future and become independent from others in terms of money. It is common to think that money is crucial for life and this is absolutely right, as money is essential for providing family and purchasing necessities. In fact, no one wants to live in poverty and be dependent on someone. For example, the most of the teenagers in Uzbekistan are studying hard to study abroad, as the salary there is much higher. Subsequently, people have to earn money to cover all their living expenses.
Turning to the other side of the argument, some people might tend to be hard-working, as they have their own goals. In more detail, this people might have experienced bullying in their past and this could be the reason. Einstein, for instance, in one of his documentaries mentioned that he decided to become a mathematician to prove his childhood bullies that he was able to achieve remarkable things.
To conclude, even though some people are determined to work hard because they follow their own rules. I firmly believe that the desire of many people to work hard is to gain money, as the worldview of people nowadays is based on achieving high goals.