People are warm and cold, and they know it. This is a very philosophical famous saying, which reveals the practical problems in interpersonal relationships. In such a hypocritical world, people often hide their true thoughts and feelings for their own selfish interests, and sometimes even show obvious hypocrisy and dishonesty. However, real friends and relatives in life will gradually show their true character and feelings in the test of time. Therefore, we must keep a sincere heart at all times, cherish those who treat us sincerely, and let us learn to respect others, be kind to others, and treat others with the most sincere attitude, in order to obtain true friendship and happiness.