Rabbi Avraham Pam related the following:

There was a Jew who, in spite of having lived his entire life in dire poverty, remained steadfast in his faith, and prayed with intense concentration.  Someone once overheard this man reciting the morning blessing, “Blessed are You… Who has provided me my every need,” with great joy.

Asked the passerby, “Can you really say that your every need has been provided for? You are among the poorest of the poor!”

The man replied, “Can one really know, on his own, what his particular needs are? If God has made me poor, then obviously this condition is necessary for me to fulfill my purpose in life. Poverty is what my soul needs, and I have been granted this in full measure!”

We ask for “a life in which God fulfills our requests for the good,” in the special blessing in advance of every new month. It would seem that the phrase “for the good” is superfluous; certainly a person would not request that which is bad for him! This, explained R’ Pam, is precisely the point.  We can never be sure that what we desire is ultimately to our benefit; this is known only to Hashem, Who “keeps watch and sees to the end of all generations” (Mussaf of Rosh Hashanah). We therefore ask that our requests be fulfilled, but only in a manner that will truly be for our good.