I hate a guy so much that if I ever see him dying I would just watch
Why do you hate this guy so much? What did he do to you?
I still remember what he did to me, he hurt me like no other.
That is really wrong to hate others so much. Hate is a soul-consuming thing. Wishing someone would die is terrible.
It's too late now, I am going to get revenge.
Revenge will won't heal what has happened to you. This person may have been a horrible offender, but you should find another way to deal with them. Report them to the authorities or let others know about what has occurred.