That session restoring really annoys me when I use Firefox on a Windows machine (I rarely use it on my Mac). I have a habit of just logging out instead of closing Firefox and then logging out and Firefox thinks it's crashed instead of just been closed.
One thing that I have noticed on the Mac that annoys me is that when I try to CMD+W to close a window it doesn't work. It just "closes" a blank tab and leaves the window open. Apparently you have to press CMD+Opt+W to close a window. That gets on my nerves.
Of course, I have been known to nit-pick.
Firefox 2.0 - Worth Upgrading Yet?