Why might Finder appear broken with question marks in the toolbar? Recently I noticed some question marks appear in my finder windows. If I click one of them, my finder freezes and has to be relaunched. I can't for the life of me remember what was there that is now missing that the Finder might be looking for. Is there any way to fix this short of reinstalling Mountain Lion? Here is what my Finder looks like:
Those seem to be missing apps.

You can "fix" it by removing them:

Press the command key and click the item, move it out of the toolbar until it vanishes.

If you need to find out what those items may be, take a look at the system log:

open /Applications/Utilities/Console.app

Check the System Messages (all) and try to click one of those question marks, because you have a hang, the system will log it.