Believe it or not, even learning can become addictive. I know a lot of people that have an addiction to learning new technologies, but they never actually build anything. The pleasure of learning new things is what they crave. They learn something, then they go learn something else, then something else. Sometimes they get two or three degrees in unrelated fields. It gives them a false sense of productivity. In the end its like playing Starcraft. It does not lead to any output. Just firing of neurons within their brains.
Accomplishment can also become addictive. That's why they call it workaholism.
Usually these things result from a misfiring in the brain. Some are more impressive to the outside world than others, but none of them really satisfy the person.
