Giving satisfaction by falsity is part of a deceptive life. Deceptiveness could be caused by helplessness or habit.
Shakuni wanted to give happiness to Duryodhana by deception caused by habit. He was hell bent to make Duryodhana the king, so he conditioned himself to be a cheat. And Duryodhana did not resist.
Dronacharya was giving satisfaction to his only son Ashwathama by deceiving him, this was out of helplessness. Poverty led him to give water mixed with rice flour, as milk to his son. Ashwathama drank it, thinking it was real milk, till he drank the real milk. After tasting real milk he gave up all desire for the watery rice flour.
In this scenario Drona went to seek help from his school friend Drupada.
Drupada, now a king, rejected Drona’s friendship because Drona did not have an equal social status of being a king -- however he was willing to provide the milk for Ashwatthama by donating a few cows. But Drona’s need had changed, now he no longer wanted milk for his son, rather he wanted a bloody revenge since Drupada had insulted him.
He started looking for some one who could help him avenge his insult. He found the great kuru kumaras, especially the Pandavas, one of them, Arjuna, who fulfilled his desire. Arjuna, bound Drupada and put him at the feet of the fiery Drona who in turn was pleased to see Drupada in this bound condition. Now Drupada was humiliated and he wanted to take revenge by siring a son who could kill Drona, and sure enough he got what he wanted. He sired Drishtadhyumna as his son, who eventually killed Drona but Drishtadhyumna himself lost his life fighting against Ashwathama.
The Pandavas were fighting as they were bound by duty of dharma for assisting Lord Krishna to establish Dharma , unlike Drona and Shakuni who were fighting out of habit or helplessness to satisfy their senses .
Dharma, it directs us to uplift our consciousness by connecting with divinity by devotion, dedication and devoted to the teachings of evolved persons.
Unfortunately, the habitual Shakuni and the helpless and revengeful Drona were brought together by their desires and destiny to fight against the dharmik Pandavas .
The habitual and the helpless Shakuni and Drona were both vanquished by the Pandavas who were helping Lord Krishna.
Dharma directs us not to be adharmik either for habitual reason or out of helplessness.