Berachos 32b

Sorry for the long hiatus. Boruch Hashem I now have phone service again, and here goes the next installment of this eSefer!

Gemara: "R' Chama the son of R' Chanina said: If one sees that one prayed and was not answered, one should pray again, as it says, 'Hope to Hashem - strengthen your heart and hope to Hashem.' "
Contrast this with the following gemara on 61a: "R' Huna said in Rav's name: One's words should always be few in front of Hashem, as it says, 'Do not confuse your mouth, and your heart should not rush to say something in front of Hashem, because Hashem is in heaven and you are on earth, therefore let your words be few.' "
The first gemara seems to say that one should keep on praying for one's needs as much as possible, while the second one seems to condone minimalization of prayer.
The Maharsha (on the second gemara), says that the gemara means that if something bad happens to a person, he/she should not pray overmuch that the bad thing be fixed, because maybe it is a blessing in disguise.
Loosely basing ourselves on that, we can say that the first gemara is not referring to a situation where something bad happened to a person - rather the person is praying for something positive to occurr.