"Why doesn't the one I buy look like the one in the ad?"

This morning one of my favorite photography blogs PetaPixel,  shared a movie from McDonald's Canada:

Keep in mind as you watch that the video was created by McDonald's itself, and is not supposed to be a criticism, but an explanation.

After you watch the video, you might want to know about what a "Food Stylist" is.  Wikipedia will help you out with this article: "Food photography is a still life specialization of commercial photography, aimed at producing attractive photographs of food for use in advertisements, packaging, menus or cookbooks. Professional food photography is a collaborative effort, usually involving an art director, a photographer, a food stylist, a prop stylist and their assistants".

At CulinarySchools.com you can read more:"Food stylists combine culinary art and science to prepare food for cookbook and advertising photographs, television commercials, and scenes in movies. Stylists are responsible for finding unusual ingredients and preparing food so it looks freshly made and appetizing. A culinary school degree is a must for a food stylist, as the job requires extensive knowledge of how food acts, both aesthetically and scientifically."

And then you might want to visit food stylists' web pages. Start here.