Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Worst Product Ever

This is the worst antivirus software I have ever used. It slowed my computer to a crawl. And they 'lost' my rebate submission and told me to resubmit it. Of course, they failed to tell me that the rebate offer had already expired and I was never getting my money back. Their customer service is the most incompetent I have ever encountered. I will never buy a McAfee product again.