There's a student buzzing around campus this semester who is constantly talking to any invisible presence. Now I have been known to talk to myself in short spurts, many people I know have, bit in a normal kind of way, not a clinically diagnosable kind of way such as this person.
Today, I heard loud talking in the own lab, but only one side of a conversation. My initial thought was someone talking on a cell phone, which is prohibited so I went over to politely ask this person to either take the call outside or end the call. However, when I came around my desk into the open area, there was the student, facing nobody yet engaged in a heated conversation while being very animated...and yes, I did check for a Bluetooth device - it wasn't there.
Here's the real kicker, I went over to her and asked, "can you please keep the conversation down, there are other students trying to work here?" She smiled, said, "okay" and did just that-she lowered her voice and proceeded with her conversation with the invisible person.
That was my Friday.