Mine was fine too. I was really nervous beforehand, but it was fine. The external examiner was lovely - he's a big fish in his (and partly my) field, and I'd read all his books, his PhD, his MA...... I was terrified of meeting him, but he was so nice, and put me at ease.
The whole thing lasted about 1 1/2 hours, after which they chucked me out into the corridor for ten mins while they had a chat, but calledl me back in after about 5 mins to tell me I'd passed with minor corrections - though they did point out there were a LOT of typos (so much for proofreading).
There were some difficult questions, but that's only because they want to make sure that you've written the whole thing yourself, and to make sure that you've understood your subject properly and the context within which it sits, and you can justify why you've looked thing A instead of thing B, or not compared them, or not looked at thing C instead.
The viva is basically your chance to explain yourself, justify your thesis - as others have said, it's a chance to nerd out on your subject for an hour or so.
I had a very squeaky bum moment when the external examiner said he'd decided to do a quick look to make sure I was right when I said that there was hardly any historiography on an aspect of my thesis. At that point I did think he was about to say I'd missed something really important, but fortunately he hadn't been able to find anything more than I had (phew).
Definitely have a re-read of your thesis before the viva - I handed in two months before my viva and didn't think about it at all in that time, but then about a week before the viva made sure I skim read it through again to remind myself what was in it. That was when I discovered all the typos, so I made a list and took it to the viva with me, so if they brought the subject up at least I could say I was aware of them.
They should send you a list of corrections to make, and give you a time scale for completion. I found it was better to get them done sooner rather than later and just sat down one weekend and cracked through it. They'd picked up on some of the typos as part of the corrections, but I made sure I caught all of them.