Final answer:
The Great Gatsby reflects the Lost Generation's attitudes through the characters' cynicism and obsession with wealth, which exemplify the disillusionment and profligate lifestyles characteristic of the 1920s.
Step-by-step explanation:
The aspects of The Great Gatsby that most reflect the attitudes of the "Lost Generation" after World War I are chiefly manifold, indicting the disillusioned zeitgeist of the era that author F. Scott Fitzgerald belongs to. However, if we must pinpoint specific attitudes, both the cynicism of the characters and their obsession with wealth stand out. The Lost Generation expressed their disillusionment with the era through their literary works, conveying a sense of hopelessness and despair.
Fitzgerald himself exemplifies this mood through his works, painting a stark picture of the time with characters like the modern millionaire Jay Gatsby, who embodies the profligate life, characteristic of the period's iconography. Thus, b) The cynicism of the characters and c) The obsession with wealth can be seen as direct reflections of the Lost Generation's sentiments following the tumultuous period after the war.