We know other people based on what they do. How else could we know them? And we infer all kinds of things about them from their behavior—especially from their habitual behavior.

Say someone you know is routinely late, and his lateness affects you. He may be full of apologies each and every time. He may have reasons to offer up to explain his lateness. He may claim he really, really wanted to be on time—and that may really be true.

You are what you do, not what you say you’ll do. –Carl Jung

You can’t know for sure what he’s thinking, though; you can only know for sure what he does. And it will be next to impossible for you not to draw some conclusions about him based on his behavior. Such as:

• He’s disorganized.
• He’s inconsiderate.
• He has a poor sense of time.
• He’s self-centered.

You’d likely dismiss your friend’s vigorous insistence that he intended to be on time. Actions, you might be inclined to say, speak louder than words—or well-meant intentions.

Put the shoe on the other foot, however, and the story takes an interesting turn. When it comes to our own behavior, we’re more likely to expect others to take into consideration not just what we do, but also what we intended to do (or, in some cases, what we would have intended if we’d actually put any thought into it). In fact, we expect others to accept our intentions as being even more important—and indicative of who we are—than our actions. It’s the thought that counts, right?

All of us tend to grant much more significance to what we think, intend, plan, and wish for than to what we do. So if what we do misses the mark or doesn’t live up to our or someone else’s expectations, it’s entirely too easy for us to write off the behavior, dismiss it, or excuse it. That isn’t the real me. It doesn’t reflect who I am. It’s just something I do.

I have always thought the actions of men the best interpreters of their thoughts. –John Locke

What we do says quite a lot about who we are—if not to us (because we’re not paying attention)—to other people. Other people are inferring things about us based on our behavior just as we’re inferring things about them based on theirs. If we recognize that what we do tells others who we are, we don’t have to expect them to try to read our minds in order to understand us. Of course, that means we need to pay more attention to what we do—as well as to what we say we’ll do.

*Slight apologies to Rene Descartes.