Self-consciousness is a heightened sense of awareness of oneself. It is not to be confused with consciousness in the sense of qualia. Historically, "self-consciousness" was synonymous with "self-awareness", referring to a state of awareness that one exists and that one has consciousness. While "self-conscious" and "self-aware" are still sometimes used interchangeably, particularly in philosophy, self-consciousness is now also commonly used to refer to a preoccupation with oneself, especially with how others might perceive one's appearance or one's actions. An unpleasant feeling of self-consciousness may occur when one realizes that one is being watched or observed, the feeling that "everyone is looking" at oneself. Some people are habitually more self-conscious than others. Unpleasant feelings of self-consciousness are sometimes associated with shyness or paranoia.