Formal estate planning laws have been around long enough, that if something bad can happen it likely already has.
In estate planning, there is very rarely anything truly new and unique. When people make estate planning mistakes, they are likely just repeating mistakes other people have previously made.
If you want to know how wrong, then you should watch a recent video by The Motley Fool "Haunt You Heirs From Beyond the Grave -- With These Horrifying Estate Planning Errors and Oddities," or read the transcript.
The stories include such things as a will being written on the bumper of a tractor which had to be removed and submitted to the court, so the will could be administered. That is probably not even the most unusual place wills have been written.
Another story includes a request to freeze the head of the deceased.
Most estate planning mistakes are not quite that strange. They are mundane.
The biggest mistake is just not planning at all.
If you would like to avoid repeating the mistakes people have made in the past, then you can easily do so.
All you need to do is to get the assistance of an estate planning attorney who has the knowledge and experience to avoid the mistakes.
Reference: The Motley Fool (Nov. 3, 2017) "Haunt You Heirs From Beyond the Grave -- With These Horrifying Estate Planning Errors and Oddities."