A Reason To Speak To Him Again
Degel Machaneh Ephraim, Haftaras Ki Seitzei:
"Do not be like servants who serve their master in order to receive a reward; rather be like servants who serve their master not upon the condition of receiving a reward." (Pirkei Avos 1:3)
There is another version of this statement: "be like servants who serve their master in exchange for no reward". I heard from my grandfather, the Baal Shem Tov, that both versions are correct, and reflect two different levels, one higher than the other.
"In exchange for no reward" is the proper and greater form of avoda. Your intention in davening for something should be for the sake of Hashem. It should not matter whether or not you receive the object of your prayers. Indeed, everything you do should be for the sake of Hashem, and not for your own pleasure at all.
However, there is another, higher level which can be understood by way of a parable:
A certain person had a deep and burning desire to speak with the king. The king issued a decree that anyone who presented him with a request would have it granted. When this person who longed to speak to the king presented his request, he was actually afraid that the king would fulfill it, and then he would have nothing more to talk to him about. He preferred, rather, that the king not fulfill his request, so that he has a reason to come before the king and speak to him again.