Decisions are best taken with a peaceful and sane mind. Such decisions must be taken with proper analysis of the pros and cons.
But yes, you are right. Sometimes we have to take decisions in a haste. We don't really have much time to think through but whatever we think is best at that moment, we must go for it. Remember, there is always an equal probability of a decision going wrong or right. So don't be scared, just be positive and confident.