Instruct: Classify a given review into positive or negative sentiment.
Query: Worst Headphones I've Ever Used

I bought these headphones from a retail store before going on an overseas trip and they were the worst headphones I've ever purchased! The left ear bud was distinctly louder than the right - making it annoying to listen to anything. If I buy another Koss product, it'll be a pair of their full-sized headphones.