“You shall love the Lord your God with all your heart.” If we are angry at God because of something that happened to us or because of something going on in the world, and we are reluctant to admit our anger either because it seems disrespectful or because we fear that God will punish us for being angry at Him, we won’t be able to “love God with all our heart.” We can only love him halfheartedly. The wife who is afraid to tell her husband how bothered she is by some of his habits, for fear that he will be upset with her and perhaps even leave her, will not be able to love him wholeheartedly, and that inability will affect their relationship. The adolescent who is scolded for being angry at his parents “after all we’ve done for you,” or whose hopes and dreams are mocked by his parents, will learn to keep his feelings to himself. That will be an impediment to his being able to love his parents as wholeheartedly as he would like to.
Accepting anger, ours and that of people close to us, has to be part of any honest relationship. If the opposite of faith is not doubt but despair, then the opposite of authentic love, wholehearted love, is not anger but pretense, censoring our feelings. I don’t believe God is fooled by that, nor do I believe that is what He wants from us. God will accept our anger, justified or not, so that we can then go on to love Him “with all our heart, with all our soul, with all our might.”
— Harold S. Kushner, Nine Essential Things I’ve Learned About Life, p. 129-130.