Believing is seeing
On the inequalities observed in the way God fulfills the desires of people, Lord Krishna gives an explanation that the difference is not due to his partiality but through how people see him.
There are believers and non-believers. Even among devotees, there are those who strongly believe in God and his system of justice, despite the most difficult situations: only their own faith carries them through. And there are believers who believe in God simply because they have been taught to believe.
Non-believers however place a strong faith in themselves. Now this is very right since God is within each one of us. But since non-believers attribute every success to themselves and to nobody else, inevitably, the ego takes over.
God seems to look after some people with special care because they really believe in God's ability to do so.
One version of a traditional story tells of the little boy who lived in a village and had to go to another village to attend school. To do so, he had to cross through a thick forest alone. His mother instructed him to return home before sunset and added, "In case you get delayed and if you lose your way in the jungle, call out for Krishna. He will surely come to you and guide you home." The child innocently concluded that "Krishna" lived in the forest.
One day he kept playing and it was sunset when he started crossing the jungle. Terrified, he remembered his mother's words and called out to Krishna.
A shepherd boy emerged from the trees and playfully escorted him home. The child happily ran in and brought his mother out to meet his friend. But no one was to be seen. The child wondered where "Krishna", his friend who lived in the forest, had gone. On hearing this, the mother was dumbstruck. She knew no one lived in the forest and that any villager who happened to be in the woods would have returned. It was none but God who had brought her child home, drawn by his faith.