How did the Buddha define success? I read somewhere that Buddha said "Those who fear death have not lived wisely". What did he meant by "Living Wisely" ? 

I sometimes interpret this to mean that I should take a chance, quit my job, and become an entrepreneur.

What I want to ask is about mind, should I become hard work in a field according to the interest of my mind or should it does not matter, and keep on doing my work like robot (consciously).

Here's my problem: Some say that in order to achieve true success I should do something that interests my mind (so I will not be distracted or bored). If we are talking about spirituality, shouldn't what is interesting to me be less important? 

That is, should I do things that I find fulfilling so as to achieve my success, or should i just keep working hard at what I am doing now, but with more focus?

The Buddhist goal is Nirvana, But I have a family and I want to give them a better life, Why earning money is seen as attachment ?
The Buddhist goal is Nirvana and on jet to reach it is called a Sekkha. Success comes then you have reached the goal and free from all stress is accomplished (Asekkha).

Even you are are not fully accomplished, the practice may help you manage your day to day stress, until one day you do not get stressed any more.

Also do not procrastinate doing the tasks as this is the last day or moment. This would help in your worldly aspirations also.