Reality television is a genre of television programming that documents ostensibly unscripted real-life situations, and often features an otherwise unknown cast of individuals who are typically not professional actors, although in some shows celebrities may participate. It differs from documentary television in that the focus tends to be on drama, personal conflict, and entertainment rather than educating viewers. Reality TV programs also often bring participants into situations and environments that they would otherwise never be a part of. The genre has various standard tropes, including "confessionals" used by cast members to express their thoughts, which often double as the shows' narration and competitive elements. Reality TV shows often have a host who asks questions to the participants or comments on the participants. In competition-based reality shows, a notable subset, there are other common elements such as one participant being eliminated per episode, a panel of judges, and the concept of "immunity from elimination."