Harry Truman was the quintessential decision-maker. Although he wasn't educated beyond high school, he intuitively knew how to make decisions. And once he made one he was willing to take full responsibility for it. Faulty thinking is often behind the paralysis we experience when faced with important decisions. Fortunately this is rarely the case, but thinking this way makes the prospect of decision-making overwhelming.
Human beings are complex, and can react to a decision in many different ways at the same time.
Further, we can't see the future, so it is impossible to predict the outcome of a decision with certainty. The good news is that there are ways to demystify the decision-making process. If the decision is important, bounce it off a friend, mentor or trusted loved one. Don't forget to consider the risks involved with each. Chances are good that you forgot to consult your feelings and intuition.