I may be in the minority in that I liked my initial idea, liked it while working on it, but don't like it much now that it's finished. Three or four of my quilts are in this category; one quilted and done, three others that are UFOs. I'll finish them, of course; my OCD wouldn't let me do otherwise. But will I really like them? The jury is still out.
I think my change of heart is due partially to my learning more as I go along, and being exposed to better ideas than the one I had! For instance, I have a log cabin that I now don't much like because it doesn't have enough contrast; I was too focused on choosing the "right" colors and didn't consider contrast. It's just a pretty boring quilt. Another is a red and white sampler quilt. I think I'm not crazy about it because it IS a sampler, and therefore, not symmetrical enough to suit my OCD..... which is peculiar because I love scrappy quilts.