Instruct: Classify Amazon reviews into positive or negative sentiment
Query: So.. why exactly is this so highly reviewed?

So I bought this thinking it would help combat buildup on the tongue (as is a reasonable expectation)First time using it: I cut my tongue and spit out a lot of blood. That was a fun experience. However, I decided to keep at it, thinking maybe I was just too rough.Well, being gentle doesn't do anything. It removes exactly NONE of the buildup on your tongue. Looking at what it scrapes off afterwards will tell you more than any review can: this does not work. What it essentially does is scrapes off saliva, leaving the buildup absolutely untouched. It's a spit skimmer, to put it simply. A toothbrush is a thousand times more effective.