My short list of complaints after switching back to Mac included the following:
I can't reliably tab my way to pop-up menus. I can never do it in Firefox - I can occasionally do it in Safari. I'm used to rapidly filling out forms without moving my hands from the keyboard, but I nearly always have to go back and manually select the "state", and any other pop-ups.
No more! There's a very simple fix - why it's not the default, I don't know. Simply go to System Preferences and select Keyboard & Mouse. At the bottom of the Keyboard Shortcuts window, select the All Controls radio button. This will give cursor focus back to you for those popup and pulldown menus.