Instruct: Classify Amazon reviews into positive or negative sentiment
Query: I can't believe it...

The best dogs in the world come from shelters, and my new little chihuahua was perfect except he freaked out and barked non-stop at everyone who walked through the front door. It got to the point where we had to lock him in the bedroom when anyone came over. Almost from the moment I put this collar on he's been quiet. I felt bad buying it because I knew he wouldn't like it but he's only gotten spritzed 3 or 4 times and he's clearly gotten the picture... this thing is worth its weight in gold!