And muzzy, of course Firefox will have it's bugs. As will Internet Explorer. The only difference is that the Firefox bugs, fixed and not-fixed, are publicly availabe. That's why you can rumage through the bug database and craft some amount of pages that take advantage of these (publicly available) bugs, to try to undermine it's stability. EDIT: And that is what you did do. Those crashes were no accident, if they were, I might get worried (not).
Could you imagine if Microsoft released a bug database to the world with all the fixed and not-fixed bugs in Internet Explorer?