1. It happened in where(occasion)? such as offices,battlefield. 2.what is the reason cause people use it? competition of business,revenge,Jealousy in the male-female relationships. 3.Is it negative or positive?why? depends on your purpose. I suggest you discuss this topic according to these outlines.I hope it can help you.

Research your topic. Here's the introduction. The Mentalist is an American police procedural television series which debuted on September 23, 2008, on CBS. The show was created by Bruno Heller, who is also the show's executive producer. It follows the story of Patrick Jane, who, as a paid consultant, uses unorthodox methods to aid the fictional California Bureau of Investigation (CBI) in homicide investigations. Use this italki site to help you with your speech http://www.italki.com/knowledge/page/ENGLISH%20ORAL%20PRESENTATIONS1.htm