Stress, contrary to popular belief, can positively impact mental performance.  A moderate level of stress, such as that experienced before a significant event (e.g., an exam), can heighten focus and improve achievement.  Furthermore, stress stimulates the brain to produce new cells, boosting memory and mental performance.  Interestingly, studies suggest optimal stress levels can even alleviate anxiety, promoting calmness and a more peaceful approach to daily life.  While excessive stress is detrimental, the right amount enhances effectiveness.