Almost every thought you think is then concerned with past or future, and your sense of self depends on the past for your identity and on the future for its fulfillment. Fear, anxiety, expectation, regret, guilt, anger are the dysfunctions of the time-bound state of consciousness. There are three ways in which the ego will treat the present moment: as a means to an end, as an obstacle, or as an enemy. Let us look at them in turn, so that when this pattern operates in you, you can recognize it and—decide again. To the ego, the present moment is, at best, only useful as a means to an end. It gets you to some future moment that is considered more important, even though the future never comes except as the present moment and is therefore never more than a thought in your head. In other words, you are never fully here because you are always busy trying to get elsewhere.

Eckhart Tolle

from A New Earth: Awakening to Your Life's Purpose