Serial killers often have traumatic childhoods involving domineering mothers and absent or weak fathers. They frequently show early signs such as torturing small animals and having an interest in violence. While portrayed as insane, most serial killers understand their actions and lack empathy, though their motives can include sexual gratification, delusions, a desire for attention, or thrill-seeking. Common traits include torturing animals as children, abnormal strength, social rejection, turning violence and control into thrills.