What's-her-face's (Annie's?) speech at the end of The Bachelor, or, should I say, the reaction to it. That was so unrealistic, and it killed the movie for me.
[Spoiler] Would've been much funnier if the crowd had erupted violently, and they'd've had to run for their lives at the end, in my opinion [/Spoiler]
However, Jimmie's grandfather's speech on marriage was beautiful... On another note, Obi-Wan got pretty annoying in Espiode III, too.
*Greivous says something about how Obi-Wan's going to die (or the like)*
Obi-Wan: "Oh, I don't think so."
He had some other gems, too. But yeah, Natalie Portman... Oi. This may be a little harsh, but might her delivery of any line in that movie make it bad? And I actually liked Hayden better in this one than I did in Episode II, though yeah, Darth Vader yelling, "NOOOOOOOO!" was pretty strange.