Ключевые слова: alternative, angry, best, certificate, change, choose, conceptual, control, customer, depression, efficiency, emotion, evaluation, excellent, experience, expression, facial, feedback, good, guarantee, laugh, marketing, mood, negative, online, people, performance, person, positive, premium, product, quality, ranking, rating, review, sad, satisfaction, service, signs, simple, skin, smile, square, staff, success, survey, test, unhappy, user, value,