| | Motivation
I have lived with the exact same problem for many years. One the "honeymoon phase" for a project is over, people like you and I lose interest and begin searching for the next greatest thing.
The answers for me, as it probably is for you, lay internal. Meaning (and I hate to say this) that it is necessary to ponder the age old question of "what makes you truly happy".
If you are talking from a career standpoint (which is the area where I had this problem), then you have to take a long hard look at your internal guide and figure out what would make you content and fulfilled over the long haul. I bet you are one of those people who has great ideas, inspires people, and a great salesperson...but just haven't found the true calling. But its there Purple; its there for all of us. Just be patient and honest with yourself and the answers will start to unfold! Anyway, hope this helps!