The Gemara relates two stories about Rabbi Eliezer and unsuccessful attempts to pray for rain.
The Sages taught: An incident occurred involving Rabbi Eliezer, who decreed a complete cycle of thirteen fasts upon the congregation, but rain did not fall. At the end of the last fast, the congregation began to exit the synagogue. He said to them: Have you prepared graves for yourselves? If rain does not fall, we will all die of hunger. All the people burst into tears, and rain fell.
In the second story, Rabbi Eliezer led the congregation in the lengthy Amida prayer for fast days, but his prayers were not answered. At that point, his student, Rabbi Akiva, prayed for rain, and rain began to fall. When the rabbis present began to discuss why the student, Rabbi Akiva, was successful, while Rabbi Eliezer was not, a heavenly voice called out that it was not an issue of greatness; rather, Rabbi Akiva was more relaxed and forgiving, while Rabbi Eliezer was more exact and demanding. God responded to each of them according to his personality.
This can be understood based on the Gemara in Rosh HaShana (17a), which teaches that a person who is relaxed and forgiving is more easily forgiven by God, who responds to every person according to his own behavior and personality – midah ke-neged midah (measure for measure). The Talmud Yerushalmi tells the story differently. According to the Yerushalmi, when Rabbi Akiva was asked to explain his success, he offered a parable of a king who had two daughters – one who was unpleasant and inappropriate, the other who was agreeable and pleasing. It is the unpleasant daughter to whom the king responds more quickly, since he prefers to interact with her as little as possible. The agreeable daughter, however, is required to put in greater effort to receive what she wants, since he enjoys and looks forward to their interactions.