Oh my gosh, you are describing me. I hop from project to project and I always have some new "shiny" idea! That's why I end up with so many piles in my sewing room. Those are for projects on the burners! The actual old UFO's are moved to a different holding area. Sometimes I get bored with cutting out so many pieces, making so many HST, I've reached a difficult part, or I'm starting to make mistakes/getting sloppy.
It's actually no surprise that I'm like this. When I was working, I was always juggling multiple projects in various stages of completion. And I work better under deadlines.