I discovered this theory about Highly Sensitive Person (HSP), promoted by Dr. Aron in her books (see her website: http://www.hsperson.com). This is a "distinct personality trait that affects as many as one out of every five people. According to Dr. Aron's definition, the Highly Sensitive Person (HSP) has a sensitive nervous system, is aware of subtleties in his/her surroundings, and is more easily overwhelmed when in a highly stimulating environment".