And can have cons that can not only outnumber any benefits, but cause worse calamity than the supposed perpetrators did. When lay individuals assume the role of prosecutor and executioner, you are going to be dealing with each of their biases, discriminations, misconceptions, mis judgements etc, which can truly be disastrous and increases the chances of unjust penalties been issued even against innocents. What any society does need is a sound and just legal system, and rather than taking the laws into their own hands, people should work towards achieving such a state by using all their prowess and capabilities in a legal method, that will bring about positive changes and just outcomes.