Final answer:
Japan is the country where expressing personal emotions is often viewed as unprofessional, heavily influenced by traditional values prioritizing group harmony over individualism.
Step-by-step explanation:
According to a major study on cultural attitudes, expressing one's personal emotions in a professional setting is deemed more unprofessional in Japan compared to other countries like the United States, Spain, Cuba, and Egypt. Japanese culture values social harmony and group cohesion over individual expression, especially in professional environments. This cultural norm is influenced by traditional values such as Confucianism that emphasize restraint in emotional expression in favor of maintaining social order.