There are some guys who keep annoying the crap out of you, but when the time comes you NEVER get to fight them. Don't you just HATE that?

Here I'll list some, since you may not have realized you never get to fight them and you still want to play those games

Well, let's kick off, shall we?

President Shinra - Final Fantasy VII

This guy leads the evil Shinra company. He only cares about money. Capitalism at its worst, so to say. He is even willing to go over dead bodies to attain his goals as evidenced when he brings a portion of the city of Midgar down killing everybody in it, only to be able to bring up a fake news story about AVALANCHE, a eco-terrorist group (you belong to). You never get to fight him as he is murdered by Jenova (and despite belief not by Sephiroth) in a very early stage of the game.

Queen Brahne - Final Fantasy IX

She might well be believed to be the game's main antagonist due to her greed and lust of power. She goes so far as to hunt down her own daughter in order to obtain the Eidolons (spiritual godlike creatures you can summon) that are sealed in her daughter's body. She does not hold back to go in full-scale with Burmecia and Lindblum, not caring about the people who live there, just slaughtering them like rats. However she's being manipulated by Kuja, who first only appears to be her supplier of magical weapons, but who later on appears to be the mastermind behind Brahne's crimes and takes advantage of her greed. Eventually when he no longer needs her, he lures her into a trap which will prove to be fatal for her, and so we never get to fight her as a boss.

Wen Kinoc - Final Fantasy X

Kinoc is a guy with an inferiority complex because his best friend Auron was always better in everything. Kinoc is a warrior monk, just like Auron. However Auron fell in disgrace because he refused to marry a daughter of a high-priest and Kinoc therefore got second in command, very well aware that position was meant for Auron. When Auron could only get away with his refusal to marry by becoming the guardian of Lord Braska the two didn't see each other for a long time. When Auron sees Kinoc again, it appears that Kinoc had become a master and now that he was tasting power he was afraid to lose it and became a big schemer only hiding himself behind his position as a Maester of Yevon. Eventually to be killed by his fellow Maester Seymour.

Grand Maester Mika - Final Fantasy X

Except for Maester Kelk Ronso I guess none of the Maesters were "clean", but Seymour is the only one you meet in battle. Mika is a two-faced bastard who appears friendly and wise at the outside, but is a ruthless leader willing to kill anyone who gets in his way. Also not above bringing fake-news, as evidenced he blames the Al-Bhed for his own actions, knowing that due to the Al-Bhed being discriminated during the entire course of the game, anyone would buy it. Still when the situation gets too big for him to handle, he abuses the fact that he's been dead for a long time (only being tied to the world of the living as an "unsent") and that he can send off the dead, and he sends himself, as a cowardice act to flee from you.
"Naaah, disappearing on us, you rotten son of a shoopuf!" (Wakka)

Theodore - Atelier Iris 2

This guy is a really annoying chicken! He is consul of the Silvaresta Empire and abuses the power the title grants him to start war against all other nations and exploit their labor. He talks big and is very extremely arrogant. When the going gets though he shows to be a real coward not even above using children as a human shield when he feels threatened. You will get into a final confrontation with him, but he doesn't fight you himself but uses a kind of magic robot made by alchemy against you. If you win that fight Theodore is cornered and will try to escape only to be kicked out by playable character Noin, however that kick is just a scenario thing and not an actual boss fight, and that is why he's still in this list.

Lord Yuna - Breath of Fire IV

Yuna might be the most terrible guy in this list. Yuna is a minister for the Fou Empire, in Breath of Fire IV. He also acts as the personal advisor for Emperor Soniel. His allegiance alone therefore makes him your enemy. But there's more to it than just that. He is also a mad scientist. It was he who masterminded the abduction of Princess Elina, which starts the events of the game, however that is only revealed at the end of the game. During the course of the game he bugs the crap out of you by appearing and disappearing at the most inappropriate moments, taunting you and bringing you in trouble. The game also have portions in which you play as Fou-Lu (who is the final boss of the game), and there too he's annoying.

His ultimate evil scheme is revealed when you finally get to see the terrible fate Princess Elina suffered at his hands, and the cruelty of that is really beyond words. When that is revealed you really want to kill him bad, but then too he escapes only to to be mentioned again for the remainder of the game... Well at least not before you defeated Fou-Lu.

In the ending animation, in which you can actually safely assume he is one of the big reasons Fou-Lu turned against humanity, you can see that he got out of everything safely, and even worse that he didn't learn his lesson and that he's already making new plans based on the scientific knowledge he gained with his twisted science shown before, completely neglecting the negative side-effects that will inevitably have, of which it was already shown they are beyond terrible.

Thanks to that you may feel great about defeating Fou-Lu and bringing him back to his senses (as the final boss fights are pretty hard), but knowing that Yuna weaseled his way out, only to start all the misery anew gives you a pretty terrible aftertaste. It also makes that this game has a pretty opening ending since nobody can predict what will happen next (also since nobody seems to realize that Yuna is still at large).

No, don't be misguided by the fact he shares his name with a beautiful sweet girl in Final Fantasy X. Also his name cannot be stolen from Final Fantasy X, as Breath of Fire IV was released one year before Final Fantasy X came, so it's likely a coincidence.