Good intentions need favourable surroundings to fructify .This can be proved by a sensitive observation of the world. No newspaper or news channel can recount this phenomenon.
What makes one do what he or she is reluctant to do is a conflict between sincerity and surrounding. This clash is the story of the Mahabharata and Ramayana.
Duryodhana and Ravana also experienced this clash at least for a few moments, but their surrounding was insurmountable.
Duryodhana developed intense detachment from the world when he was saved by the Pandavas from the haughty Gandharvas. He decided to renounce everything and fast till death. He convinced Dushasana to rule. Karna and Dushasana failed in convincing him other wise. But when the lower beings came and convinced him about his enemity towards the Pandavas and when they promised that they would assist him, Duryodhana suddenly changed his attitude and regained his arrogance and ambition.
Another time Duryodhana agreed to accept Sri Krishna as supremely powerful, but when Sri Krishna sided the Pandavas Duryodhana excused himself and preferred to die in battle.
Ravana had unlimited power and resources. He had no reason to be lusty. Maricha, his uncle instructed him not to mess with Sita and Rama, by narrating his personal encounter with Sri Rama. Ravana like a sensible person went back to Lanka, but his sister Surphanaka, changed everything for him and for the destiny of Lanka.
For good sense to prevail one has to create a good surrounding either the external or the internal surrounding . The problem with an external surrounding is that it is always in a flux, hence one who does not work from an internal surrounding becomes an integral part of the external surrounding.
Duryodhana and Ravana are extreme examples.They were thinking of something good but their surrounding was unfriendly. No one is as evil as Duryodhana and Ravana.
Yet we see a constant clash between intentions and surroundings. Depending upon who influences whom people make decisions. Some become good with good surrounding and some wanting to be good change into doing what the external world influences them to do .
With developed sensitivity and the recreation of a strong internal surrounding through sadhana, svadhyaya sadhu-association and selfless service one can be like Vibhishana, Hanumana and Vidura whose surroundings were unfavourable but they acted upon their good intentions.
We might fail to change the external surrounding but whay about the internal surrounding?
Is it not our choice?