Today, I had someone pull me aside and ask me if I was alright; several people had noticed that I was really worked up about something the other day, to the point of getting angry at one of my coworkers.

It took me a few seconds to figure out what he was talking about, and when I did, I laughed a little. "Oh, Lucian and I go way back; we've been roommates for two years now. We're in the habit of giving each other a hard time; there's nothing wrong."

Afterward, I realized what I should have said -- something like: "Oh. I understand what it might have looked like, but actually everything's okay. We've been roommates for two years now, and I was just giving him a hard time."

The crucial difference: If someone comes to you concerned that there might be a problem, first let them know unambiguously whether there is, in fact, an issue, and then explain. If you put the explanation before the verdict, they'll spend the entire time parsing through what you're saying, trying to determine whether it makes the problem better or worse, before you give them the bottom line at the end. They'll be distracted enough to miss most of what you actually say, and then they'll be forced to change mental gears at the end from whatever conclusions they had dug into to the conclusion you then sprung on them.

The principle, I think, generalizes. If you're trying to tell someone something important (either in conversation, or, as I've found more useful, in polite debate), it's almost always a good idea to present your position, then your data, then your position again. It's really easy to forget that initial statement (which, again, should be as clear and unambiguous as possible), since for you, it seems fairly insignificant. But for your conversational partner, the difference between evaluating evidence with some idea of its context, and in a vacuum, is huge.

As silly as it sounds, we forget sometimes that other people aren't mind-readers. It should be common courtesy, then, to accommodate this inability by making yourself easy to be understood. Or at least to realize that your responsibility for your phrasings isn't limited to "explain all of the things that are true", but rather "explain all that is true, and everything that is necessary for the truth to be understood." As I spend more and more time having high-excitement discussions with people about truth statements, I should be better at keeping this in mind.