Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Sappy and brittle

This guide gives you even slices from almost any size loaf, but the unfinished wood bleeds sap in puddles and the plastic is so brittle you have to be very careful when you're cutting. Brush up against the guide posts with the knife and more often than not you're going to break at least one. Mine lasted 6 months before I had to replace it.