"What happened three years ago totally changed the melody of his life, and it's a song I can't wait to play for you." (14) (Metaphor)
Young uses this metaphor when speaking directly to the audience in the Foreword to The Shack. He likens Mack's life to a song, and his encounter with God at the shack to a change in the melody or main tune of that song. This metaphor primarily shows just how big a change occurred in Mack's life; like a change in melody is immediately and intuitively apparent to a listener, Young implies that the shift in Mack was sudden and noticeable. There is something particularly meaningful about comparing Mack's life to a song, because throughout Mack's time at the shack, he repeatedly hears Papa and Sarayu singing or humming tunes from the future and even his own past. These moments of song, starting with this quote and continuing at the shack, link the themes of memory and time.
"The Great Sadness had draped itself around Mack's shoulders like some invisible but almost tangibly heavy quilt." (27) (Simile)
Mack uses The Great Sadness as a euphemism for depression throughout the book. Depression and crippling shame and guilt are things the author experienced in his own life, in part due to sexual abuse as a child. The author draws on that experience to produce vivid metaphors and imagery about grief, such as in this quote, where depression is likened to a quilt wrapped around Mack's shoulders. A quilt is usually something that would evoke coziness and comfort, but by emphasizing heaviness in this simile, the reader understands how Mack is so tangled in his thoughts and feelings that he struggles to live normally and open himself up to others.
"Like grass pushing through concrete, the repressed feelings and fears somehow began to poke through." (76) (Simile)
Like the simile above regarding The Great Sadness, in this quote Young uses a simile to express Mack struggling to acknowledge and understand his emotions. Mack experiences this feeling when he is driving to the shack, unsure if he will meet God, come face to face with Missy's killer, or find he has fallen for a cruel prank. Mack has fought to keep his feelings inside, both since Missy's disappearance and especially since receiving the letter from Papa. Comparing his feelings to grass pushing through concrete gives the reader a sense of Mack's lack of control of the natural process of emotions; though he has tried to keep this nature repressed, it will find a way to come to the surface.
"When we three spoke ourselves into human existence as the Son of God, we became fully human. We also chose to embrace all the limitations this entailed...It would be like this bird, whose nature it is to fly, choosing only to walk and remain grounded. He doesn't stop being a bird, but it does alter his experience of life significantly." (101) (Simile)
This metaphor is one of the most important in The Shack. Papa uses this metaphor in a long conversation with Mack about freedom, limitation, and trust. To illustrate the way God, through the existence of Jesus, is both human and non-human in form, Papa compares God in the form of Jesus to a bird choosing not to fly. The ability to fly is still present, but the bird limits itself for a specific goal such as resting or eating. Later in the conversation, Papa extends this metaphor to humans choosing to live in or outside of God's love, meaning it unduly limits a person's experience to live without God's love. By using a bird in this comparison, Papa both makes it a very clear and physical image and demonstrates to Mack how simple it is for one type of animal to understand self-limitation.
"Memories spilled through his mind like rats fleeing the rising flood." (159) (Simile)
Like the simile about grass pushing through concrete, Young again physicalizes Mack's emotions in a time of extreme distress. In this case, Mack experiences the feeling because Sophia tells him that he is "here for judgment" (159), leading him to think that he has died and is going to be destined either for Heaven or Hell. This simile likens Mack's old, perhaps repressed memories of misdeeds entering his mind all at once to a pack of rats running away from a flooding area. This simile is bold, sinister, and gross in a way that immediately signals the dread Mack feels in the moment. And, like in the case of the grass pushing up through cracks, a flood is a natural phenomenon; Mack has no way to stop, reverse, or control the process.
