Thank god it's not just me! I always found finishing a game to be extremely difficult - to the point where I have stopped making them all together. After being done with 90% of a game you still seem to have 90% of the work left to do. kylemaxwell is right that this happens with many endeavors but it seems to happen with games the most.
This reminds me of the Pareto Principle :
It takes 20% of the total time to reach 80% of the project.
It takes the other 80% of the time to achieve the remaining 20% of the project.
https://secure.wikimedia.org/wikipedia/en/wiki/Pareto_princi...
One of the most important thing I've learned.