State law will determine who gets your property and how it will be divided, ignoring your preferences.
The Probate Court will appoint a Guardian to make decisions and manage money for any minor children. The person you would have chosen as Guardian may not be selected.
The Probate Court will appoint an Administrator to handle your estate and run your business before it is distributed to your heirs and require the Administrator to pay for a bond with your money. The person you would have chosen as Administrator may not be selected.
Your financial situation will become a matter of public record and your family's financial privacy will be impaired.
It may take more than a year (in some probate cases, much more) to complete the probate and distribute the assets to your heirs. As long as the Probate Court has control of the estate, your family will have to ask the Court's permission to sell real estate, conduct the sale of a business, and otherwise manage your affairs. Under these circumstances, it is difficult to manage assets for growth or obtain fair values for assets that are to be sold.
The money available to your family will be partly used up by probate costs, including Administrator's fees, Guardian's fees, probate referee's fees, attorney's fees, and court costs.
You may incur estate taxes that could have been avoided.