A person's character is reflected by his actions. We might not always be consciously aware of our actions, and why we react a certain way, but more than likely our actions reflect our persona and tell the outside about who we are. Referring to the story "Love in L.A." by Gilb, we feel as if we know Jake, the main character through his acts. The story doesn't tell us much about his character, but we still manage to get a pretty good picture of his personality through his performance. What we do, or fail to do, say a lot about our character. Simply telling somebody that you will come and visit or implying that you love him or her does not have the same impact as if you actually do it. Another importance is that our actions should match our words for us to be true to others; because we all say and do things we didn't mean to at one point or another. You will probably learn more watching somebody than listening to somebody. Though I believe that there will always be some things that we won't reveal about ourselves through actions but most likely we won't speak about everything concerning ourselves either. I think we express many of our feelings through actions, consciously or unconsciously. Another example of a character we got to know pretty well through his actions was Sonny in "Sonny's Blues" by Baldwin. We feel like we know how he feels and who he is, yet he hasn't told us much about himself.
Bottom line, I sense that you can definitely get to know a person by his actions, because actions speak louder than words. It's not what we think; it's what we do that shows us who we really are.