No, a person's eyes cannot change color depending on their mood. Eye color is determined by the amount and type of pigment (melanin) present in the iris, which is the colored part of the eye. The amount of melanin is primarily determined by genetics, and once a person's eye color is established during infancy, it typically remains stable throughout their life.
However, certain factors such as lighting, clothing, and the surrounding environment can create optical illusions that make it seem like a person's eye color changes slightly. Additionally, emotions can influence the size of the pupils, which can give the appearance of the eyes appearing darker or lighter, but the actual eye color itself does not change based on mood.