3  For I was envious of the arrogant when I saw the prosperity of the wicked.
...
21 When my soul was embittered, when I was pricked in heart, 
22 I was brutish and ignorant; I was like a beast toward you. 
23 Nevertheless, I am continually with you; you hold my right hand.
...
28 But for me it is good to be near God; I have made the Lord GOD my refuge, that I may tell of all your works. 

It may seem that life is unfair and that those in power are prospering while those who put their faith in Jesus fail. But the whole of Psalm 73 is a realisation that hope is in God, not the actions of humans. Focusing on human injustice goes nowhere; God will deal with this, and we have hope because we can trust God implementing His plan for judgement and justice.