Following is a cautionary tale on never saying anything in private you wouldn't want repeated publicly. Names have been changed.
We here at 5D have an intern working for us...we'll call him Scone. Coworker John, Scone, and I all work in the same room, although we can't see each other because of the dividers between us. This fact led directly to the incident.
Scone is a smart and articulate kid, so I sometimes forget that he just doesn't have much programming experience yet. He came to me with a programming problem, so I told him the solution.
"Well, the obstacle avoidance behavior file is conditionally compiled based on the mission flag in the CMake file, which is currently set to mission_dave in your virtual machine. Since the behavior should be unconditionally compiled in now, you'll have to move it out of the conditional and into the normal list of included files."
It makes perfect sense, right? Apparently not, because Scone gives me this blank stare like I was talking in German. That was doubtful, since I don't speak German, and I realize it just went right over his head. I go over to his desk and walk him through what he needs to do, although I'm a tiny bit annoyed because I'd rather him play around and attempt to figure it out on his own for a few minutes before coming to me.
A few minutes later, someone walks out the door heading in the direction of the break room. For some reason, I think it is Scone, which means John and I are left alone in the room. I start talking, which incidentally is where a lot of my problems throughout my life have come from.
Me: "John, do you think I'm helping Scone too little? Or too much? Because I just don't think he's getting anything I'm saying."
So yeah. There were a few frantic moments while I mentally went over what I said, trying to think if it was too insulting or patronizing. Had I said Scone wasn't the sharpest knife in the drawer? Had I mentioned anything about a light being on but nobody being home? Because I could have easily said something like that, just joking of course, but not the sort of joke you'd want to say to someone's face.
And apparently, not the sort of the joke you'd want to say if you're not absolutely 100% sure of whose face you're talking to. And even then, probably not, because you don't know what your listener might pass on, or what microphones are hidden around, or who might be just around the corner.