As you're probably aware, she's not my favourite companion, I didn't like her that much in The Runaway Bride, but when she became a regular taking over from Martha I became annoyed, luckily Martha appeared 5 times in that series so I was okay with that, and Donna won me over in The Fires of Pompeii and she brought emotion and comedy to the show. If I had to rank the companions she'd probably come about 5th, but she is by no means my least favourite companion.