You're in your office, working on something. You have 30 minutes, 15 minutes, or 5 minutes until your office hour starts. Perhaps you have the door open to fit in with the department ethos and appear collegial. But what you're working on must be done soon.
Someone knocks, or doesn't knock. Perhaps a colleague comes in to shoot the breeze before the meeting she stuck around for. Perhaps you hear a cheery, athletic "Hey, Doc, I was passing by and since you're here, I just need a little help on my homework."
Perhaps you've closed the door, but the dept. chair knows you're there, so when there's a knock you answer it. Perhaps the knocker is a shy ESL student with frothing white goobers on his teeth. Perhaps a second, very needy student was already lurking and feels she's entitled to come in too.
Three times this semester I've asked brightly, "Oh, did we have an appointment?" and then turned the student away until the appointed hour, closing the door and feeling terribly callous. Right next to the dept. chair's open door.
I didn't say that to the senior colleague (who I like enough), and she sat down while I continued to look busy, hoping she'd get the hint.
THIRSTY: Do you turn away walk-in students outside of office hours? Do you limit colleagues' visits? How?