You know the one I'm talking about. You can't wait to fight this boss, and the longer you go without getting to that fight, the more amped you get. Not because you're excited for the challenge, or because you know beating that boss will open up the next major sequence. No, this has nothing to do with game advancement. This time, it's personal.
Maybe this boss has been hitting you from behind the entire game. Maybe this boss has done some truly appalling things over the hours. Maybe this boss just rubs you the wrong way. Whatever the case you just can't wait to reach this boss and put him in his place. You can't wait to go head to head, to show him that for all his talk, all his evil, he can't stand up to you. You can't wait until he's nothing but a memory, a memory that ends with your victory. This isn't the guy you were excited to fight because you thought he might be tough. This is the monster that you just hated and wanted to take down.
For me, it was Dalles from Ys II. The odd thing about him is that he recognizes you as a threat from the beginning, but still runs his mouth anyway. He's essentially the right hand man of the main boss. He is part of a group of monsters terrorizing the land of Ys, though Dalles himself can pass for human. He's dressed in a black cloak, and is mainly a wizard.
(mild spoiler warning)
As you travel through this game you come into contact with atrocity after atrocity commited by Dalles. The first time is when you get a town where everyone is mysteriously hostile to you. The only way to progress is over the bridges that lead in and out of this town. The north bridge is raised, and the operator will not lower it to allow you to pass. It turns out that Dalles came and kidnapped the operator's son to hold him hostage and turn the town against you. When you finally rescue the boy, he makes a mention of being scared that he might starve. Another town you reach is nearest to the monster's nest, a shrine that the monsters took over, which used to be the seat of power on Ys. This town has been under constant attack, its residents periodically kidnapped to be used as sacrifices. Every day they can hear the five chimes of the bell tower that signals another sacrifice. Dalles' handywork again, and he still has the audacity to walk through this village passing as a human.
In the shrine he gives you a chance to turn and run, and when you don't take it he curses you into another form. Somehow, he believed that would stop you. Later, you find some people you were looking for hidden away after escaping the prison where sacrifices were being held. One of them you befriended early in the game. You think you've saved them, but Dalles was really just following you. He shows up and curses them as well, and taunts you about how powerless you are. By this point, I'm really looking forward to taking him down, but of course, I have to cure my friends of the curse first.
The kicker is in the bell tower. You arrive there just as a sacrifical countdown has begun. You can't reach the altar, and the girl there tells you to save yourself. Instead you race up the tower, the bell chiming away, and arrive a moment too late. Once again, Dalles is the culprit, and once again, he taunts you before warping away without a fight. You make your way back down the tower and see the girl there, apparently dead. As you exit the tower back into the shrine, the music changes, perfectly reflecting how I now wish to tear apart every monster in my way, but none more than Dalles. I've defeated every major enemy he's thrown at me, and I absolutely cannot wait to take him down.
Finally, I reach him. This fight has it's own music, which is pretty crazy. To be honest, I didn't find him to be that tough of a fight. In both of my playthroughs of Ys II I was able to take him down on the first try. That didn't really matter to me though. At that point, all I wanted to do was scream his name as I ran in to tear him apart. This is what I did, and watching him go down was extra satisfying. Dalles was everything a villain should be. Not just another enemy to slow you down, but the guy who gets in your head and gets your blood boiling. The one you'll stop at nothing to beat. I love Ys II, absolutely love this game, and my own personal feeling against Dalles are probably a huge reason why.
As an honorable mention, I would like to add that if you got the chance to fight Sodia from Tales of Vesperia, she might be in the same vein. Wow but she ticked me right off. Anyway, I'm sure plenty of you have good stories on this matter, and I'm eager to see what bosses really affected you like Dalles got to me.