But recollection can also trip us up. For one, we have poor memory. The more we remember an incident the more we distort it. So I seem to remember "how I used to go ... with shouts of joy and praise among the festive throng" (42), glossing over all those other blemishes I'd rather not remember. The sense of the strange indifference of God wearies me when, by the rivers of a place I do not call home, I remember Zion and what it used to mean.
So does the psalmists' practice of recollection do more harm than good? Does it clot the blood or rip the wound open again? I think what makes the difference is what we remember. The psalmists call to mind (1) God and who he is, (2) the acts of God throughout human history, and (3) God's Law. So the psalmist is not trying to remember all those subjective experiences he had of God, fallible as they are. Remembering my own past is easy enough; my depression lends itself to easing into thoughts of the glory days. The psalmist instead focuses on the objective fact of God: who he is, what he has done in the large scheme of things, and who we are to him.
And I guess this is why I'm writing a blog - to help myself think about "whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable..." I write to help myself think of the culmination of all these qualities in one being, God. I do not know if God will cure my depression or loneliness, but maybe I will find some bit of comfort in thinking in him.