Eren Yeager failed his test for several reasons. Firstly, his relentless pursuit of freedom and his desire to protect humanity from Titans often consumed his thoughts, leaving little room for studying or academic pursuits. His single-minded focus on these goals may have caused him to neglect his studies, resulting in a lack of preparation for the test.
Additionally, Eren's impulsive nature and tendency to act on emotion rather than reason may have contributed to his poor performance. His fiery personality and quick temper could have led to careless mistakes or overlooked details on the test.
Furthermore, Eren's unconventional upbringing and traumatic experiences, such as witnessing his mother's death and living in a world constantly under threat, may have affected his ability to focus and concentrate on academic tasks. These experiences likely shaped his priorities and worldview, placing less importance on traditional education.
Overall, while Eren is a skilled fighter and determined individual, his focus on matters outside of academia and his personal struggles may have led to his failure on the test. It serves as a reminder that even heroes have their weaknesses and areas for improvement.