And since I was talking about house rules, you would be incorrect.
Most people, when they are discussing collaborative games are talking about collaborative world building. As far as house rules, you can always suggest something but as DM I retain the right to say no because people have proposed crazy stuff. I mentioned the guy who wanted to be a werewolf above, another wanted to be a half-vampire dragon. Not dragonborn, a character that had all the abilities of a vampire (but could walk around during the day of course) and had dragon wings.
That, and I run for multiple groups so I don't have a lot of house rules and in order to keep things straight I use the same house rules for every game. I can always explain why I do something but odds of changing are slim.