Gosh, I like SillySusan's answer. That would change my UFO list considerably, lol.
My problem is that I everything up to putting a top together. Choosing fabrics, cutting, putting units and blocks together. Somehow, that's where I stall. A combination of boredom with a project, trying to arrange blocks so that not too many of the same fabric comes together at seams (large, scrappy quilts are my typical projects) and the challenge of keeping blocks in the right place. I don't know why I just let those blocks languish!
I have probably 6 or 8 "kits" because I have learned the hard way that I have a specific pattern in mind for a fabric, then forget about the pattern, or can't find it when I want it, and use the fabric for something else. For example, there was a pattern that I'd seen in a magazine that used a stripe for sashing. It was a CW pattern, and the stripes done in blues in the sashing played an important part in how complicated the pattern looked. A while later, I found a perfect fabric on sale, knowing I had that magazine someplace. After going through scads of magazines, I gave up, thinking maybe I'd recycled it or passed it along. Of course, I later found the pattern. Anyhow, those kits are not UFO's for me. Nor are the rarely purchased kits.
If I haven't started cutting/sewing, to me, it's not a UFO.
I am working on being more like KalamaQuilts. I have a list of UFO's that I'd like to make significant progress on, if not finish, this year.
Finished for me is usually a completed top. Most of the time, I don't have a recipient in mind when I'm sewing. I quilt by check (send to a LA). So for me, tops are easier to store as well as not involving a large expense. They get quilted as money allows, or when I realize I have a perfect top for somebody. I do keep the binding or binding fabric with the top until that happens.