Addiction is all around us. Whether you like it or not, our brains are wired to like one thing, over and over, a whole bunch. Most likely you'll never get sick of something you're addicted too--well, maybe a little. But you'll always come back, because it fills a need that your body and mind have grown to love. You'll most definitely get sick if you refrain from doing it. And that can be bad.
Addiction comes in many forms. Naturally, physical addiction can have the most outwardly obvious effects. Heroin, methamphetamines, nicotine, caffeine, alcohol, prescription pain killers are just a few. Then there are the combo physical/mental ones. These usually take the form of food items such as chocolate or ice cream, but in the publisher's case, it can be as wild as minestrone soup from Gino's.
There are other addictions. One of the more bizarre is self-mutilation. Tattooing and piercing could be considered addictions because there is a high degree of psychology that goes into them.
Mental addiction is perhaps the most sinister. Addicted to love, sex, aggression, adrenalin, hate ... emotions that fill our brains with endorphins we grow to crave. People can have an addictive effect--a charisma, perhaps, that keeps you coming back for more. I wonder if relationships--with the inevitable co-dependency--are some form of addiction?
My current addictions are simple. I have a caffeine addiction that reminds me with a headache on no-coffee days. I'm also addicted to a computer game. World of Warcraft has been filling a social gap for me lately. It's also balls-out fun. If you play it, look me up. I play a Gnome mage named Zit on the Greymane realm.