A person should never make an important decision alone.
Decision making is considered very important because it decides the success of work. Taking decisions alone is too risky, it will affect the family life and sometimes may ruin someone's life. It depends on how big or serious is the matter to take a decision. We usually become confused while taking important decisions alone. I agree that a person should never make important decision alone.
First of all, it depends on individual opinion in making decision of their own, if a person is too independent and very practical person prefers to go by their own guts. Whereas, since centuries some people consult their important things to others, which helps them to take a good decision. For instance, parents make decisions on behalf of their children for many things, it may be about their studies, jobs, wedding and many more.
In addition, there are difference in fields of experience and difference in the life experiences, or some people have experienced a kind of same situation will be the best person to guide and help to make a decision. And also, varied culture, age group, gender, etc all add to diversity of group which gives us varied perspective and enhances the the kind of ideas the group contribute more information and more knowledge to decide on something better.
Furthermore, reduces the chance of mistakes and failure. Making good decision is crucial in every level of life. Risk level is reduced by consulting two or more people and also more alternatives are likely to be generated. For instance, people consult when it comes to money matter, when they want to invest or buy some thing expensive they do contact their friends, relatives or well-wisher to make a decision.
In short, humans are the one who make errors, so it is better to consult others before making a big decision in life. Otherwise we are the one, who suffer when mistake is occurred. By consulting others we get more knowledge, information by experienced person.
Your guidance and patience no matter what I was doing has helped develop me into the person I am today, thank you!