Karma Yoga is a selfless act. Any work which does not directly fulfill your ego is Karma Yoga. If someone's tire is punctured and you stop to help, that is spiritual work. If you remove a nail from the road because you think someone may step on it, that is Karma Yoga. How you perform an act makes it Karma Yoga -- and not what you do. The spirit of Karma Yoga is an internal thing. No one on the outside can tell if someone is doing Karma Yoga or selfish action.
Suppose your aim is good but a situation still makes you angry?
Selfishness. Somewhere there is selfishness.
How does one avoid attachment to one's own duty?
It's very hard to avoid attachment when we have strong desire for the world. Attachment gives reality to desires. You desire ice cream but if you have no attachment to ice cream, that desire will be forgotten very quickly.
The question is, how to remove attachment? You do something and the first thing that comes into mind is, "It's for me; I am the owner of it." If we start seeing our actions as for the world and what we are doing as part of the world, then gradually the mind becomes nonattached. It will not affect your activities in the world. Only the mind's relationship toward action is changed. One should make an attitude of selfless service in all actions and thoughts.
What is non-attachment?
The term "attachment" is a little hard to understand. When we say "nonattachment" it sounds like not caring or not feeling any responsibility. For example, a farmer and his laborer plow a field and sow seeds. After working hard together all day, the laborer leaves. At night it rains so hard that the field floods and the seed is destroyed. How does this affect the farmer and how does it affect the laborer? The laborer worked harder than the farmer but he isn't affected by the destruction of the seed. His attachment is limited to his duty. These are two separate things: 1) attachment to duty 2) attachment to doership and ownership.
To do your job thoroughly and do your duty well it would seem that you would have to think about the fruit of your labor.
The "duty" term includes working with complete concentration, cheerfulness and thoroughness. You have a duty to your family. You think, plan and create a livelihood; that is important. The attachment that develops is the cause of pain, anger and fear. But your mind cannot separate from expectation of the fruit. We must realize that the fruit is not in our hands. [...]
You mentioned performing one's duty perfectly. What does that mean?
It means not to leave the work half done, not to be trapped in dualities or your physical comfort. Keep your enthusiasm up.
--Baba Hari Dass, a silent monastic at Mt. Madonna, in "Selfless Service: The Spirit of Karma Yoga"
SEED QUESTIONS FOR REFLECTION: How can we stop ourselves from judging the selfishness of others, based on the wisdom that no one can know whether the act sprang from Karma Yoga or selfish action? The author traces selfishness as the root of anger, even when the intent is good - what is your experience on this? Can you share a story from your life that illustrates the difference between Karma Yoga and selfish action? What do you understand by "performing one's duty perfectly?"