First, I would like to relate that the life of prayer is a mystery. It's not a telephone call. It's not email. It's not even Google Chat. Real spiritual conversation is somewhere between the interior silence felt by so many in our culture and the "hey I was just talking to God" attitude of many televangelists and other religious fakers.
One of my favorite commentaries on the spiritual life is from the beloved Saint Francis of Assisi. In his Admonitions, the following is included as Chapter 28:
On Concealing the Good Lest it Be LostMany anti-religionists will point out the absurdity of faithfulness to a God who you cannot see, touch, feel or hear. They cannot resist capitalizing on Mother Teresa's confessions of spiritual loneliness as further evidence of this absurdity. They do all this without acknowledging the absurdity of accepting creation without a creator; a far greater discrepancy.
Blessed the servant, who stores up in Heaven the good things, which the Lord shows him and does not desire to manifest them to men in view of wage, because the Most High Himself will manifest his works to whomever He has pleased. Blessed the servant, who watches the secrets of the Lord in his heart.
I love my fiancee. She whispers things to me that I would not share with anyone. She acts, at times, in ways that would seem absolutely ludicrous who was not privy to the intimate details of our relationship. The messages that lovers send each other are not meant for the world at large. The Lord is a Lover like no other. His methods are not subject to the scrutiny of men. Note that Blessed Teresa asked (sincerely, I think) for her letters to be destroyed. She knew they contained the privileged communications of her Beloved.
The Lord uses all kinds of means and methods to to increase our love for Him and for our fellow men. Mother Teresa's constant reminder was that the suffering of our age was not primarily physical, but spiritual. She described loneliness as the greatest epidemic of our times. Blessed be the God who allowed her to receive a double helping of this suffering, for His greater glory and for our salvation.