This tactic gives off the romantic feelings Charlie has for Sam and how important he is to the plot. The other main visual effect used to enhance the trailer is the use of "title slides". These slides are used to reveal things to the audience, for example, when the first one used begins it says "Charlie never stood out until he found friends who let him in", you also learn the names of his new friends through use of these slides. Slides like these are a very productive advertising tool since the viewer must read the slide and then mentally and fully engage in it