I love it a) because it's kind of wrong and taboo, but they're adults and it's kind of kinky b) because it some ways I think it's canon, because they are attached to each other emotionally, very strongly, so it's kind of incestuous even if they aren't having sex and c) because both actors are really fucking hot.

It's also really wrong because they're brothers, and because Dean practically raised Sam, so there's a real power imbalance there, particularly if their relationship stems in some way from childhood. Power over one another and the potential for their relationship to be abusive make me feel kind of wrong shipping them.

Yep, that's what I love about Supernatural - feel ALL THE THINGS!