In Bhagwat Geeta your chosen duty is described as 'swadharma'. Everyone has to carry out their swadharma without carelessness and ego. Also while performing one's chosen duty, our attention should be on the quality of action, rather than being attached only to the fruits of action.  There are two types of fruits we get out of any activity -- main fruit and subordinate fruit. For instance in a game of sports, the main benefit we get is that of enjoying the game & physical fitness and the subordinate fruit can be winning. Even if we lose, the main fruit is not going waste. Both winner and loser get physical fitness & enjoy the game.

In life, the main fruit of discharging our duty properly is purity of mind which comes if one discharges duty ethically. With purity of mind we get peace of mind, harmony and ability to enjoy what we have, without getting disturbed for so-called pleasure objects which we do not have. Subordinate fruits are wealth, position, rank, name and fame. Even if the latter does not come, the main fruit of purity of intellect is always obtained in any karma yoga, which is of main importance.

We also forget, or do not notice that God is giving us the main fruit of being happy and contended, even if other things are not coming in ample measures. God has already given us so much by way of infrastructure of free oxygen, water and sunshine. Is that not good enough reason for us to feel grateful and in return give our own contribution to make this world a better place still? Can an ungrateful person be ever happy in life?

This does not mean that we only live on air and sunshine. As per the infallible theory of karma phala, one will definitely have good results for good work done. But moment we try to be selfish and work only for money or position, we mostly end up compromising values and ultimately create problem for ourselves. So the Gita’s message is:  'Do your best always, do not be utterly selfish and be grateful'. That indeed is the art of karma yoga.