I was just looking at the Challenges and one was the UFO challenge and I was thinking the same thing, why do folks have some many unfinished projects? I don't. I have 3 that need quilted on my longarm and my DH was redoing that room and although I could still use the machine, there aren't really any walls or at least insulated walls and I would freeze although that might make me quilt faster.
I do have lots of fabric and I buy more not for specific projects but I'm getting close to retirement age and I fear I won't have extra money to buy so I buy now. But there is always the thought in my head that what if I die, where will this fabric go? To a dumpster or someone using that bolt of fabric as a paint drop cloth. My goal will be to buy less. As for unfinished projects, I always think the same: how much did this cost me, how much time have I invested and how sad I would be if it was unfinished and got thrown away after I was gone. No one would ever throw away a quilt, perfect or imperfect. At least I don't think.
Think of the ultimate goal and don't start something new until you finish what you started.
Good luck ladies.