I'm not just going to shoot them and hope some court thinks I had the right to do so. If a court convicts you on murder charges then you spend the rest of your life behind bars.

Well, I don't know where you are from, but over here you can kill a theif and not goto jail. And not surprisingly, of the 20 years I've been alive, my house has never been broken into. (although stuff has been stolen from outside of the house so I did answer Yes on Roger's poll.)

Think about it. If someone shoots your mother/father dead and then you find out who did it. Does that mean you can go
kill him/her for killing your mother/father. Nope. You'll goto prison.

Avenging your mother/father's death would be premeditated murder, which would be a lot different than self-defense.