Intention
Intention is a peculiar concept. It cannot be grasped by any of the five sense, and it can only be felt. But this feeling can radically change our approach or reaction. Its such a powerful notion, particularly because it is so abstract. Even how it is defined is all in the mental realm. By pursing a career in healing, it has strengthened my belief that others can feel when you are really trying to help them, or just going through the motions. In other words, they can feel your intent. And patients will respond accordingly.
Its difficult for me to describe this, but its something I want to discuss. I am just glad we have this word. A name to put on something so intrinsic and wonderful.
In Chinese, the character for intention: 
It is poignant because in this character, it has the character for “heart” in there, recognizing the source of where intention comes from.