Did I Scare Ya?

Do you know what holiday I don't understand?
Halloween.
I don't understand this holiday.
Small children, dressed up as other people/creatures knocking on random strangers doors asking for food.
What. The. Heck.
Like, for real? Who created this holiday? Who was the first person who said, "Alright, kids, go knock on that person's door and ask them if they have any candy they would like to give to you!"
...I don't understand...
Okay, I get little kids wanting to dress up. I get that. I really do.
What I don't get is the whole trick or treating bit.
Also: When you say, "Trick or Treat!" what does this mean? Does this mean you would gladly take a trick just as well as a treat? Is there really even a choice? Is this question just a courtesy? Would I get arrested if I tricked a kid?
Why do we even tack that word on there if not to use it? Shouldn't we just shove our Walmart bags under stranger's noses, and say, "GIVE ME CANDY NOW."
I mean, in all honesty, that's what we're doing now.
And I don't get it. I really don't get it. I don't understand. (On a side note: Why candy? Why not cookies? Or carrots?)
So, guess what I'll be doing on Halloween this year?
Turning the porch lights off and eating my candy (that I refuse to give to small children who probably have enough hyper in their bags to last them a year) in a dark room.
Boo.