Obsession is a state of being possessed with someone or something. It is often referred to as an unwanted thought that intrudes into a person's mind. In art, if an artist produces in one's art an accumulation of an impressive mark, gesture or material then such art work is said to be obsessive. In psychology, it can be termed differently as obsessive-compulsive behaviour. Works by folks who are not taught or technically and professionally trained usually exhibits obsessed art works, and many critics make powerful arts and cases out of such obsessed works.