I love the feature where I paste something into an email, and then it stops me typing by popping up a useless menu.
My second favourite is the one where you're typing, and suddenly it starts treating all your keypresses as shortcuts and deleting things. I love that.
And don't even get me started on Outlook search. I can no longer find any emails, even by typing in the things that were on them.
But hey, at least an admin can fuck it all up from one place!