There are few things women never seem to get enough of:
Having one brownie recipe is like having one single dress. Even if it's plain perfect it just won't suit every occasion, mood and day... You need a messy, over the top brownie recipe on hand for your broken-hearted girlfriends while you also need a fancy and quick brownie recipe for a barbecue among friends.
Those are the unwritten rules of girldom.
I might be thinking this too much through, I know.