Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Why haven't you bought this yet?

Firefly is easily the best thing that ever happened to television. If you disagree, then just throw out every television you own. In fact, go to the nearest electronic retailer, buy a television, and then throw it out.This show is amazing, and just looks better on Blu-Ray. (Arguably Brown-Ray would be better)Seriously, if you don't like this show, then there is something wrong with you.