How people pick films they want to see

Most of my friends decide on what films they want to see by seeing if they like the storyline of the film and also if there is an actor or actress they really like and will go see the film even if they dont know anything about the film they will see it just for the actor. Also if the film has a good review and other people have seen it and say its really good they will go watch it and if the trailer of the film looks good. And the type of genre effects the films they see for example if there is a new musical or horror movie they will go see it just becuase of the genre. And if the film was a book thats been turned into a movie like Harry Potter and New Moon they will go see it to see if the film has stayed clsoe to what the book is like.