Waiting for one of my co-workers to get out of a meeting so that they can confirm that I'm doing this thing they just trained me on correctly, and will not totally fuck up the system and cost us $3000 when I click "Enter."
It's surprising just how much of my job has seemed to consist of either waiting for other people to do their jobs, or waiting for them to get out of meetings (which I suppose is something similar, since in my experience, many meetings are just things that keep me from doing any real work.)