For all the jokes, pornography addiction is a real and actual addiction. Really. Stop laughing. I'm serious. Porn works like any other addictive substance: It re-wires your brain in ways that make you need it, and probably proves harmful to the rest of your life.
Basically, the visual images of pornography associate themselves with the dopamine release you receive from pleasure. And in turn, you become less sensitive to sexual images, meaning it can become harder for you to be turned on by reality. You'll also be compelled to seek out porn more and more often, of course. Like any other addiction, you can shake porn addiction through prolonged avoidance of the material, but you're going to go through withdrawal symptoms along the way. It's a pretty har-- tough. It's a tough one to shake. [YouTube]