deliberately misrepresented or caricatured my argument - ensure you stick up for yourself!
remember that although you need to be intellectually rigorous, you also need to submit a document (the thesis) within a reasonable amount of time - saying "that wasn't possible in the time I had" is a perfectly legitimate answer!
remember YOU gathered the data, not them - quite a few times I had to just keep repeating "you may believe that to be the case, but that wasn't what I observed" until they left me alone
It's true that they want to test how much you know and to do that they ask questions you don't, or couldn't, know the answer to. At one point I started to answer a question and half way through realised I actually meant the exact opposite of what I was saying - I admitted this and the external simply said "yes, it's a difficult issue, I don't know how to answer it either".
I really hope I'm not making this sound scary - it certainly wasn't easy, but they were so encouraging, generous and understanding. And I think if I had had an easy ride I would have felt a bit ripped off, after all, it is meant to be an examination. Also, the time flies by - it felt like I'd only been in there half an hour.
Hope this helps,
Heifer