Is it normal to think about/plan murders?

Wondering what ppl think. Is this kinda thing "normal"? I spend many hrs a day thinking about killing ppl, and not random ppl they have to look a certin way, if they fit the critearia, I plan it out to the T. Then I fight the urge to do it. Sometimes it keeps me awake. Here is one recent example so you get the idea. I saw a man in a bar I don't normally go to, he was the right hight, right build, right hair color, even drove the right car. So the plan was to wait out by his car use ether to knock him out, gag, tie him up, take him to a field, carve out his eyes, shoot him in the head, use chemicals on the body in a shalow grave.