Instruct: Classify Amazon reviews into positive or negative sentiment
Query: diabolical junk

This was the most incredibly time-wasting, useless piece of junk that I have ever encountered. Horrible design: Grandaddy (who has a Ph.D. in science) spent hours struggling to get it to work. Never did. Tubes were bent and occluded, so we could not get the fluid into the chamber, precluding any use of the elaborate set up that might or might not have produced some interesting effects. Shame on Mad Science for marketing this abomination.Sad grandad