Do actions and Don't crave results

Once I watched a video of Luke Belmar, he said:

A farmer does not sow the seeds and sit on a chair waiting for it to grow. Instead, he prepares correctly by ploughing and tilling the soil. Then he sows the seeds. It doesn't stop here, he waters it, protects it from insects, adds manure, plucks weed. After all this, the seeds germinate into plants. Action = Reaction

Everything has a cause and that cause is created by action. According to Mahabharata:

All the creatures in the world would have been exterminated, if there were no action. If also acts bore no fruits, creatures would never have multiplied. It is even seen that creatures sometimes perform acts that have no fruits, for without acts the course of life itself would be impossible. Those persons in the world who believe in destiny, and those again who believe in chance, are both the worst among men. Those only that believe in the efficacy of acts are laudable. He that lieth at ease, without activity, believing in destiny alone, is soon destroyed like an unburnt earthen pot in water. -- Section XXXII - Vana Parva

But why should we not crave results? It is natural to do it. But we should not.

Results are a sign of attachment to something material.

Consider two engineering students, the first one thinks if I study well I will get a good job and good money, the second one thinks If I study well I can make the world a better place by inventing great things for good people. The first one does work for material possessions, the latter does it for the sake of work. He enjoys it.

Doing action without the desire of results, lets you enjoy your work.

Cheers!