LEIA: Only you could be so bold. The
Imperial Senate will not sit still for this, when they hear you've attacked
a diplomatic...

VADER: You weren't on any mercy mission this time.......Several transmissions were beamed to this ship by Rebel spies.
I want to know what happened to the plans they sent you.

LEIA: I don't know what you're talking about. I'm a member of the
Imperial Senate on a diplomatic mission to Alderaan...

HAN: (yelling) Yahoo!

And yet, James Earl Jones, Carrie Fisher and Harrison Ford were still somehow able to deliver those lines convincingly (cringe-free). Hmmmmmm...........

So, based on that, I've determined that the acting in the Prequels sucked slightly more than the dialogue. ;-)