Generalists ship.
Got this link via but the summary is this:
What separates a generalist and a dabbler? Generalists ship.
Generalists finish things, produce things, have end-points and accomplish them. They may accomplish things in many fields, but they do finish them.
This is a weakness of mine. Oftentimes I trail off after a strong start. It may be worth considering, for me, to have goals based on process rather than specific products - to have my goal be to make products of some sort, and accept that I will ship things across many domains, and that I'll have to explain that to people constantly.
This way, at least, I'll have things to explain them with.