Thriller films come in many subgenres characterized by their moods, such as action thrillers which provide excitement and surprise, or psychological thrillers where characters are mysterious and audiences cannot identify the good or bad guys. Thrillers aim to immediately engage audiences by confusing them with puzzling ideas and clues, hooking viewers to try and solve the mystery as small hints are revealed. Common thriller techniques include red herrings, plot twists, and cliffhangers, which villains often drive forward to thrive as the driving force of these ideas.