The book of Psalms contains many songs of comfort and encouragement, but there is a voice within the Psalms that is far from reassuring. Instead of projecting heavenly peace into earthly confusion, these other songs are cries of pain and anguish.
I find that a great help. When I struggle with crises my depression is often compounded by the suspicion that I shouldn't be feeling this way. And as I open the book of Psalms, what do I find? These great heroes of the faith went through crises that made them hurl angry questions at God. When I see this, it helps me understand that I'm not a dismal exception to the rule that Christians are strong and joyful all the time.
Songs like Psalm 44 are included in the worship manual of God's people because its anguished stanzas can speak for us whenever we feel embittered by life's unfairness.