shameless repost of my thread on reddit
I love smug Aku as much as anyone else ("your journey through - how did you say it - 'this miserable Aku-infested world' continues!") but there's just something so satisfying about Aku being at a loss for words. Some examples:

• The title quote from Jack & the Zombies - Aku's eyebrows go out and he realizes he fucked up.

• Of course, the classic All right, Jack - WHERE IS THE SWORD?!

• From the newest season, when Aku realizes he's done: "Oh no." Bonus points for him being so scared, he's out of character. No big "OH NO", just a small whimper as he knows he's dead.

I'm sure there are tons more, but these are the first that come to mind.

What?

Can't wait until Samurai Jack: Infinite when it turns out Aku was always just Jack from the future after having gained great power which transformed him, and gone back in time to set his own origin in motion, sealing his fate as he did.