Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Two questions:

1- Why do you feel the need to force quit?
2- Which app are you trying to force quit?
 
Some apps seem more troublesome than others in this regard... on Leopard at least. Safari and Photoshop CS5 come to mind.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.