I find myself continuously wanting to start new things. I'm like a dog chasing cars.
Lots of motivation with no discipline.
What about just putting the idea on a list and pruning it once a week? Why is my last fascination no longer relevant? Why don't I finish it?
Knee-jerk motivation -- rather than calculated, planned motivation -- is a great way to end up with a graveyard of barely started projects.
Changing focus is fine. Just make it a conscious decision.