As babies, we were easy. One cry meant you were hungry. Another meant you were tired. It's only as adults that we become difficult. We start to hide our feelings - put up walls. It gets to the point where we never really know how anyone thinks or feels. Without meaning to, we become masters of disguise.
It's not always easy to speak your mind. Sometimes you need to be forced to do it. Sometimes it's better to just keep things to yourself, though. Play dumb. Even when your whole body is aching to come clean. So you shut your mouth, keep the secret, and find other ways to make yourself happy.