The Myers-Briggs Type Indicator (MBTI) is a personality questionnaire designed to identify certain psychological differences according to the typological theories of Carl Gustav Jung as published in his 1921 book Psychological Types.
...INFPs are quiet, creative, sensitive and perceptive souls who often strike others as shy, reserved and cool. These folks have a rare capacity for deep caring and commitment--both to the people and causes they idealize. INFPs guide their behavior by a strong inner sense of values, rather than by conventional logic and reason. Forced to cope with this facts-and-figures "real" world we inhabit, INFPs may appear to have been imported from another galaxy! They gravitate toward creative or human service careers which allow them to use their instinctive sens of empathy and remarkable communication skills. Strongly religious, spiritual or philosophical people, INFPs may see the purpose of their lives as an inner journey, quest or personal unfolding. More practical or rational types may tend to discredit the INFP's sources of understanding as mystical. The search for a soulmate is a preoccupation for many INFPs, who must balance their need for privacy and peace with their yearning for human connection. If there seems to be an air of sadness in the INFP's spirit, blame it on this type's longing for the perfect in all things.