I have one that I started about 15 years ago...my very first attempt at quilting. It was a queen-size with 'bulls-eye' or 'does & darts' (or something like that) for the blocks. Nothing like choosing a complex block for your first attempt. I ran out of patience and didn't make another attempt until a couple of years ago. This time I did it right and started out simple.
That quilt top is very close to finished, but every time I take it out and think about finishing it, I just look at how NOTHING lines up on it and think how much work it would be and never get around to it.
Somehow, I have finished each project I have started. It is my goal to not have any other quilt top or other project sit around unfinished for 15 years ever again!