Instruct: Classify the given review into positive or negative sentiment.
Query: Flat

What's so great in this book? The characters lack profoundity, and I soon tired of them, because they were so nondescript in personality (other than glitz and glamour) that I lost all interest, given also the oblomovian lack of emotion they display whatever happens to them. As for the humour, this novel has as much fizz as a can of cola drink left open for a week. It just didn't catch.