Personally, I detest Halloween, but it's not because I think it's some kind of an "evil" holiday. I don't even remember liking it as a kid, to be perfectly honest. I know that I am part of something like a 1% (or less) minority, but here are my reasons:
1. I have seldom found a comfortable costume. I like to dress very simply with loose-fitting, relaxing clothing. When I'm wearing a costume, I'm almost always uncomfortable, tugging at it to keep it fitting the way it's supposed to, etc. It's too tight or awkward to move around or sit in or it's too long and you keep tripping over it or something like that. If you wear a mask that just covers the area around the eyes, it seems to shift around so that you can't see well. If you wear a mask that covers the entire face, you can hardly breathe and it's unbearable hot and stuffy.
2. Where I live and grew up, October 31 is almost always pretty darned cold. I can remember as a child, my mother made us the most gorgeous, elaborate, detailed costumes imaginable. She was an excellent seamstress and we always had the neatest costumes of any of our friends. We'd wait until dark and then get ready to go out trick or treating. We'd get all dressed up and would then have to put a coat on top of our costume to keep warm. Nobody would even get to see our costume. We wouldn't wear gloves because it was just too awkward to take the candy and put it in our bags with gloves on, so by the time we got home, my hands were absolutely frozen. I was aching from being outside for so long, even with a coat on.
3. At least 70% of the candy people give out is crap. I've never had much of a sweet tooth anyway, but I can remember dumping out my candy on the living room floor when I got home. I hardly ended up eating most of it. A few people would give us apples. Who gives kids apples for Halloween? You're supposed to get candy, not fruit! And homemade popcorn balls that fell apart in the bag and were pretty much mutilated by the time you got them home.
4. I hate the gore, the blood the distorted, gruesome faces, the fake knives through the heads, guts spilling out, etc. They were never scary, just disgusting.
5. I hate having to keep getting up for hour after hour to go to the door. I can't get into a TV show at all and even reading is hard. You just have to sit in your living room doing nothing, waiting for the doorbell to ring. You just set seated again and you have to get up again. It just goes on for hours!
6. I even hate Halloween colors. I'm not much into black at all, except that I absolutely love black cars. I like orange with other citrusy colors like lemon yellow or lime green and I like it with autumn colors in flower arrangements, etc. But black and orange together are just gaggy.
That said, I don't think it's a satanic holiday or any such nonsense. My church -- the ever-conservative Mormon Church, even has a Halloween party for the kids, so we definitely don't oppose the holiday. It's just me. I know, everybody is going to tell me what a horrible attitude I have. I don't care. That's how I feel.