Here are Forbes articles with some real life examples of issues with DIY wills or improperly drafted ones.
ran into a situation a while back where a guy died intestate, which in TX means that his wife gets half of their house, and his minor children by a prior marriage got the other half of their house.
so wife #2 owns 1/2 of the house and the hostile ex wife #1, who was the custodial parent of the minor children, was de facto co-owner of the other 50%.
Not good.