What is important to guido?Identity examples of Guido doing whatever is necessary to protect what is most dear to him

Guido loves solving puzzles, so riddles deeply appeal to him. He is particularly skilled at solving them, and Doctor Lessing comments that Guido is truly remarkable in this regard. This facility with riddles is a metaphor for how Guido deals with life. He loves to find solutions to difficult problems, and he is always looking for ways to charm or protect those around them with his quick, insightful mind.

When Doctor Lessing tells Guido a riddle at the dinner party, shattering Guido's belief that the doctor is going to help him and his family escape, the gravity of Guido's situation is contrasted with the inherently trivial nature of the riddle. Before the Holocaust, life was far simpler, and the "problems" with which people occupied themselves were of a far lighter sort, involving dramatically lower stakes. Riddles (or, perhaps, quotidian problems) seem surreal and silly in comparison to Guido's present situation.