Driving.

[Buffy obsessed fan]

Not sure if this was ever brought up, and it's kinda unimportant, but I was thinking about it; In 'Graduation day part 1' I think, Anya was talking about her car and driving and what not; so obviously she could drive. Then in 'Triangle' Anya makes the statement 'I didn't know that I couldn't drive, 'til I tried' or something to that effect. How would she just be discovering driving if she drove two seasons prior to that?

[Cangel]

Well as far as I know Joss didn't plan for Anya to take such a big role in the show, so I think at first they didn't consider all the facts about her (like somewhere in s1 it sounded like Buffy was a senior when we later know she wasn't). Even her last name was different back in s3 (it later changed from Emmerson to Jenkins I think) so if nobody was paying any attention there, chances are high they simply forgot about the driving skills as well.

[Kana]

I've seen this asked before, I think. My reckoning is that it isn't inconsistent because we never actually see Anya driving. So when she was planning on driving with Xander, she was probably thinking of trying it out there and then. One assumes if Xander had taken her up on her offer then she'd have the exact same conversation with him whilst trying to drive.