Unlike the real world, it is programmed to be constantly exciting, interesting, and attention grabbing. Therefore, it is not an accurate representation of the real world. For example, there is a disproportionate representation of beautiful people. If you want to see what real people look like, head down to your local DMV or farmer's market. This leads to people thinking that the world is a very dangerous place, when in fact, violent crime rates have been dropping for decades.
Television skews our perception of reality.
This is how the broadcasting companies make their money. And you can't say that advertising doesn't work, because it does. If advertising didn't work, corporations would not spend millions and millions on it every year. The purpose of advertising is to create desire in the audience. To do so, they need to make you feel like what you have is not good enough.