Well, I can't exactly say for sure, since there hasn't been a lot, but if I had to choose, I'd say the one at the Litwick Mansion. Litwick are cute and cool, but it was funny when Cilan said he had an explanation for everything, then just ran in terror when the statue fell to his side. Plus, the part where they were at the portal to the other world was epic to me.
Well, after a while (2 years maybe, I dunno), you build up a protection against her insults and stuff to try to get youinto an argument. After that, once in a while, you can easily get back at her for the stuff. Don't worry, I'll live from it XD