One important similarity between Bruno and Shmuel in John Boyne's The Boy in the Striped Pajamas and Annemarie and Ellen in Lois Lowry's Number the Stars concerns the depth of their friendships. Annemarie cares so much for her Jewish friend Ellen and the Rosen family that she even considers if she would sacrifice her own life for Ellen. While she dismisses the thought as a fairy tale, she later learns that her own sister Lise and her fiance Peter did indeed sacrifice their lives for the sake of the Jews. Both Lise and Peter were involved in the resistance movement, and Peter was executed, whereas Lisa was run over by German soldiers. Similarly, though Bruno does not die for Shmuel's sake, Bruno becomes so devoted to his friendship with Shmuel that he promises Shmuel to help him find his father within the concentration camp if Shmuel can bring Bruno a pair of striped pajamas. Ironically, the day that Bruno crosses into the concentration camp on the other side of the fence is also the day Bruno's father has engineered the first mass murder of the Jews within, leading to Bruno's untimely death, hand in hand with his friend Shmuel.

A great contrast between Annemarie and Bruno is their level of naivete. Both characters realize their lives are different and miss their lives before the start of the war. For example, Bruno misses his old, luxurious home, whereas Annemarie misses Tivoli Gardens, the town center where families could socialize, ride the carousel, and watch fireworks. However, Bruno is completely oblivious that there is death and destruction going on in his world that his father has an operating hand in, whereas Annemarie is very well aware of the threat the German soldiers pose to the Jews in Copenhagen. Since Annemarie is wiser about what's going on the world, she is able to act bravely for the sake of Ellen, even ripping the Star of David necklace from her neck to hide her from the soldiers and helping her and her family escape to Sweden. In contrast, Bruno remains completely oblivious about why Bruno and his people have been rounded up into the concentration camp and blindly becomes his father's own sacrificial lamb.