I run up to things and punch them? No, really. I once spent an entire Sha mc session punching my own pet to death. Then I went to work on the bear tank. Needless to say that did not end well.
While running my Mistweaver Monk through some dungeons, I got MC'd by a boss. This nearly wiped the group because my stance was changed which swapped my hotbars and after the MC wore off, it took me longer than necessary to figure out why I was punching things and not healing.