John Hagel wrote a great article on passion v. obsession : Edge Perspectives with John Hagel: Passion Versus Obsession.

He has a couple of great points:

Passion pulls to the edge, while Obsession pushes to the edge

Passion achieves potential, while Obsession compensates for inadequacy

Passion broadens, while Obsession narrows

Passion expands relationships, while Obsession inhibits them

Passion creates options, while obsession closes them.

While he doesn’t discuss this, I’d like to think that passion and obsession can work well together.  I personally think that a little obsession is healthy at times.  Narrowing focus, inhibiting relationships and closing options, may help in productivity.