You've probably had the experience of being in a really good mood or having a great day until WHAM!...you lose a client without warning, have a friend or significant other stand you up, or get criticism from your boss on a recent project. Regardless of what triggers it, you now find yourself spiraling into negative thinking, and in some cases, you may get so upset that you literally make yourself sick or go to a depressed, dark place.
The truth is, it happens to most of us—maybe even ALL of us. We allow other people or events to make us feel hopeless, sad, or to control our mood and happiness. Basically we "give our power away" to these external events and let them have temporary control over our inner selves.