Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Worthless!

Claims to kill fleas. My cats brought some in just as we went on vacation. Upon our return, fleas were all over. We tried all the J&J flea killers. All worthless. By worthless I mean the fleas treated the pooling RAID products as a swimming pool, splashing around for apparent fun. When they got tired, they hopped away. We brought back the empty cans and demanded a refund.