Your house is too big: When you buy a house that is bigger than you can afford or need, you end up spending extra money on longer debt payments, increased taxes, higher upkeep and more things to fill it. Some people will try to argue that the increased value of the house makes it a good investment, but the truth is that unless you are willing to downgrade your living standards, which most people are not, it will never be a liquid asset or money that you can ever use and enjoy.
You fail to take advantage of opportunities: There has probably been more than one occasion where you heard about someone who has made it big and thought to yourself, "I could have thought of that." There are plenty of opportunities if you have the will and determination to keep your eyes open.
