I find, my joy is in opening the door (of my house) on a bunch of unsuspecting people, and screaming 'Trick or Treat' at them before they get the chance to say anything...
It's kinda fun watching the thought processes going beyond the conditioning of "They open the door, they scream trick or treat, they expect something".. :)
I think that's about the time they actually realise there may well be scary things abroad that night.. The grinning apparition at the door being one of them. :)
Malk
On halloween, I go as myself. That really scares people. :)
Back in college I did that - went around the dorms doing trick or treat. Most students didn't have anything, so we came prepared with bags of chocolate and we gave them out. Weirded people out, but we got to meat lots of folks.