It's a habit.
Because they have bad genes.
Because their horns don't work!
When there are no attachments
Thought of this one on my own while playing WoW a couple days ago and I'm pretty sure it hasn't been told before. I like corny jokes. I Googled it and didn't find anything (:
It's a habit that stuck from when they were slaves.
It takes 21 days to make a habit.
Attire