You can't kill the Big Bad! If you kill the Big Bad, you'll be just like him!
Yeah... so those dozens of henchmen fodder I killed to get to the Big Bad don't count for anything then, huh?
Oh, look! After our long struggle and hardships, we're right at our goal here. Let's stand around and congratulate each other for the next ten minutes instead of stepping through the portal/destroying the evil thing/actually finishing our quest/etc. OH NOES! The bad guys got here and ruined everything while we were standing around like idiots.
