Even after over a year, I still don't fully understand, or want to, the discussions on the following, and therefore avoid them like the plague. In fact, I think most of them scare me a little.
The Fly Lady. (WTF?)
Cleaner debates.
Mooncups.
"What's for dinner?"
Buying and selling.
Quinny Buzzes. (I used to think it was some sort of drink until I googled it.)
Any more?