Confidently lamenting

Psalm 27, Psalm 28. The opening six verses of Psalm 27 are a song of trust (1-6) followed by an individual lament. I haven't spoken much about form criticism (pioneered by Herman Gunkel) in these postings, but this is one of those psalms that doesn't neatly fit into the categories. Gunkel puts the second part into the lament category, following expressions of trust and confidence. This lament includes the image of seeking the face of the Lord, a recurring theme in the Psalms, where the psalmist expresses feelings of abandonment by God.
I like the idea of confidently lamenting. It's easy to complain or plead for help, but it shows the depth of the relationship when the psalmist voices the lament in the context of praise and trust. It's like conversations I have with old and trusted friends, where we move quickly from one topic to another, knowing that the strength and length of the relationship can handle the ups and downs. "The Lord is my light and my salvation; whom shall I fear?" v.1, followed by the plea: don't hide from me, don't leave me.
A quick note on Psalm 28: here's the first reference to the Lord being a shepherd (v. 9) after the famous and familiar shepherd psalm (23).