In the novel Extremely Loud And Incredibly Close, Oskar often uses "heavy boots" as a metaphor for his depression. When he knows he is heading into a potentially upsetting or disappointing experience, he often says that his "boots feel heavier". However, I noticed that as he matures (towards the end), he stops using this phrase to convey his feelings. I think that his quest to find the key is what causes this change. This "mission" is the way that Oskar deals with his grief and mourns the loss of his father and I think that it is what helps him get over some of his depression. On page 52, Oskar says, "Every time I left the apartment to go searching for the lock, I became a little lighter, because I was getting closer to Dad." I thought that the change in Oskar's depression was significant because it shows how he is recovering from his loss. Foer uses the weight of shoes to represent Oskars feet, which take steps forward in his life. Therefore, the harder it is for Oskar to take steps, symbolizes the harder times in Oskars life moving forward.