Insanity means being insane, and it is used to describe many different things. Insanity quotes are available that describe various situations and events that may drive someone out of their mind. Insanity may also be called madness, craziness, or being mentally unstable. Using this word to prefer to someone is rude and inconsiderate, unless the individual has entered an insanity plea in court to answer criminal charges. Many commercials and other marketing methods use the term insanity to describe low low prices or easy financing, but to someone who has a mental illness this term is offensive and degrading and should never be used. There is a saying that insanity is doing the same thing over and over and yet expecting different results.