Excerpt from The Power of Now, by Ekhart Tolle

"As long as the egoic mind is running your life, you cannot truly be at ease; you cannot be at peace or fulfilled except for brief intervals when you obtained what you wanted, when a craving has just been fulfilled. Since the ego is a derived sense of self, it needs to identify with external things. It needs to be both defended and fed constantly. The most common ego identifications have to do with possessions, the work you do, social status and recognition, knowledge and education, physical appearance, special abilities, relationships, personal and family history, belief systems, and often also political, nationalistic, racial, religious, and other collective identifications. None of these is you."