Why Olaf Came to Life Headcanon
When she and Anna were children, Elsa created snow from her magic and they built Olaf as an inanimate snowman. Yet he didn’t come to life like he does later in the movie. Why does he come to life later? Here is my headcanon reason as to why he does.
During “Let It Go,” Elsa recreates Olaf during a moment of relief and newfound freedom and out of the cheerful memories of the time before Anna’s accident. It also represents how the isolation from Anna hurt Elsa as much as it hurt Anna.
As she creates Olaf, Elsa sings, “Can’t hold it back anymore,” which reveals how much she really wanted to build a snowman with Anna whenever she (Elsa) was asked. The relief, happy memories, and intensity of her long-held desire are the reasons as to why Olaf was brought to life.
In that case, Elsa’s later surprise when she discovers Olaf is alive (especially since she clearly did not know that he was) may indicate that she never even admitted to herself how just badly she wanted to rekindle her friendship with Anna.
And just think about it: if Olaf hadn’t come to life, Anna would not have been saved from Hans’s attempt to kill her, nor would Elsa have been saved by Anna.