From time immemorial we are suffering or enjoying the fruits of our activities.
For example, if I am a businessman and have worked very hard and smart and have earned a great amount of money, then I am an enjoyer.
But if I lose all my money, I am a sufferer.
Similarly, in every field of life we either enjoy or suffer the results of our work.
This is called karma.
Although we are suffering or enjoying the results of our activities, we can change the results, and this change depends on the quality of our knowledge.
We are engaged in various activities but we do not know what sort of activities we should take on in order to gain relief from the reactions of these activities.
These activities can be changed when we are in goodness, when we are in sanity, and understands what sort of activities we should perform.
This is explained in detail in the great book of wisdom, Bhagavad-gita.
