Drafting a will isn't the only step that you take when planning your estate. It's an important one though. It allows you to document what your final wishes are for your financial assets, business and property toward your heirs. Countless testators voluntarily draft their wills every year. Some are forced to do so under duress, however. You may be able to contest a will if you can prove that the deceased drafted it under the undue influence of someone else.
It happens all the time. A disgruntled relative was left out of a deceased individual's will or receives far less than they expected to get from the decedent's estate. They decide to try to right the perceived wrong and contest the will.