Please analyze the tweet "I got a NO RESPONSE again from an #irate customer of #amazon 😞😞\nwhy can't they understand that it's not always amazon fault..\n#carrierfault" and classify its emotional content. Choose from the following emotions: anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust. If no emotions are detected, respond with "neutral or no emotion".
anger, disgust, pessimism, sadness