Rather than an actual annotation, I'd like to include a section of Wikipedia's article on Mythomania, also known as pathological lying.

A pathological liar is someone who often embellishes his or her stories in a way that he or she believes will impress people. It may be that a pathological liar is different from a normal liar in that a pathological liar believes the lie he or she is telling to be true—at least in public—and is "playing" the role. He or she sometimes is seen to have a serious mental problem that needs to be rectified.

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Pathological liars often actually convince themselves that they are telling the truth, which in turn can alter polygraph tests and other questioning. Some have observed that when caught in a lie, pathological liars tend to become hostile or try to disregard the fact they lied; often playing it off as a joke.

A compulsive liar will resort to telling lies, regardless of the situation. Again, everyone lies from time to time, but for a compulsive liar telling lies is routine - it becomes a habit and a way of life.