Our quality of life depends on how we feel on the inside. If we feel restless, our quality of life is not very good. If we feel peaceful, our quality of life is good. And how we feel depends on what we think, what we say and what we do. In the physical world, this is easier to understand because we have physical guideposts available to us. If you want to go to City A, go left. If you want to go to City B, go right. Or we could rephrase this as: If you go left, you will reach City A. If you go right, you will reach City B.
Such physical guideposts are missing in our mental life, so we need to create them on our own. You need to make various decisions on a regular basis, and in many instances, these decisions are to be made in very different roles that you might be playing — a professional, a spouse, a parent, a colleague, etc. While the decisions could be of a very different nature in each of these cases, all of these decisions can be made using a single set of personal guidelines. These guidelines apply to each of these decisions because they exist at the root level.