Perhaps there's an additional element of needing to punish the enemy for continuing to plague you. We tend to personalize the player characters, and their fight becomes our fight. Therefore, when a bad guy just keeps coming back to harass, we take it personally, and drive even harder to eliminate the menace. When the enemy is vanquished, even for a short time, we feel the full catharsis as though we had gone through it all physically ourselves.

Which begs the question: should games end with the destruction or death of the villain? If driving him off gives such satisfaction, is a more permanent solution more satisfying? That would seem to be a direct correlation with how evil the enemy is, and that's something that has to be built up over the playing time of the game. It can be easily mishandled; make a villain too melodramatic, or have him be voiced by someone without the right level of finesse, and the character collapses into absurdity. Ideally, we want an enemy to be arrogant, self-centered, pitiless, and perhaps insulting. We want him to embody the traits that we find obnoxious in real life, so we can feel true pleasure in dispatching him. We imagine that killing this character removes these negative elements from our world, and that's a worthwhile pursuit.

In sheer gameplay terms, however, killing the bad guy at the end of the game means having to start the process all over again in the game's sequel. Reinvesting emotions in a new enemy requires more energy than simply fighting the old one again, and it can be difficult to determine which scenario is more believable. Games like the Final Fantasy series, however, make a habit of reiterating on the antagonist so many times during the game that by the end of it all, you're quite ready to say goodbye to him for good. The typical emotion at the end of the final boss battle is triumph mixed with relief.

Are any of the incidental enemies worth any emotion? The cannon fodder that get strewn in your way that are just there to help you get stronger for your final confrontation with the villain of the piece, are they even in the same league? No, of course not, but if you gave them long enough to pound on you, they'd do just as good a job of ending your adventure as any of the higher-level opponents would. So we see that every obstacle is important, it's just the ones that talk back to you that are worthy of our ire.

In the end, it can be said that we need our enemies as much as they need us. In fact, our player characters wouldn't exist without them. And the more annoying, the more personal that enemy is, the more we need to defeat him. Maybe someday a game will come along that turns the tables on us -- where we think we're the heroes of the story, when all along it's us who were the villains. Then we'll get to see how it looks from the other side of the equation, and know ourselves fully for the first time.