Although many examples can be cited, taking a look at the life of two eminent personalities of India would suffice our contention. The first of the two is Verghese Kurien, the father of white revolution in India, while the second is Prof. A.P.J. Abdul Kalam,who is tipped to become the next President of the country.
When Kurien applied for the Government of India scholarship to pursue higher education (he was a mechanical engineer) in the U.S., he was told that there was no scholarship left in his field and he could avail one in dairy technology. Finding no other alternative he opted for it but when he reached U.S., he was told that he could pursue education in the field of his choice. This came as a pleasant surprise to him and provided the much needed respite. When he came back to India, he was asked to go to Gujarat where the Amul Cooperative was being set up. One had to serve the government for a stipulated period as it was the government which had sponsored the trip. All his arguments and pleadings that he be given an assignment in his field fell on deaf ears. With heavy heart he went there, with the intention of leaving once the bond period was over. But destiny had something else in store for him. He worked there for whole life, and the rest is history. A mechanical engineer finally ended up working all his life among cows and cattle. It was probably in his destiny to be in such a profession. Although it did not happen at the first instance when Kurien went abroad, but got manifested when he returned.
The case of A.P.J. Abdul Kalam is also similar. He wanted to become a fighter pilot. But he failed to make it, which left him dejected and drew him towards spiritualism. But an ardent `Karmayogi' that he was, Kalam did not lose hope and instead decided to make planes, even as he could not fly one. The journey in which he forayed, made him the most eminent defence scientist of the country.
Had he become a fighter pilot, India would have probably lost a great scientist. Contrarily, had he stopped performing `Karma' after failing to become a fighter pilot (which was his primary objective) he probably would have been lost in the oblivion. But as it was in his destiny to become powerful and eminent, which was supplemented by continuous `Karma' (action) in right direction. He became A.P.J. Abdul Kalam, the father of Indian missile system.
What is clear from these two cases is that one has to perform `Nishkama Karma' (Karma without desire). Gita says "Karmanye vadika raste ma phaleshu kadachana", which means that one should go on performing action without thinking about the result. One has to remember that success is not in his hands. He will get the desired result if God has stored it in his destiny.
My conclusion- Its very important to make efforts but the outcome is not entirely in your hands there is this force bhagya or destiny that plays the role.