Sometimes we just make decisions and wish them to turn out to be good decisions. Sometimes we don’t evaluate the risk well; sometimes we don’t study the situation deeply enough; sometimes we don’t have the expertise required to analyze the problem and no experts around to consult.
Jack Zenger and Joseph Folkman listed the habits that lead to terrible decisions on an HBR blog: http://blogs.hbr.org/2014/09/9-habits-that-lead-to-terrible-decisions/
It is worth checking the list before making decisions. We cannot always guarantee good decisions but at least we can try to avoid the habits to make bad decisions.