I hate to bring the sorcerer bloodline stuff up again, but it's a great example of what I'm talking about. Take this one line in the PHB:

Some sorcerers claim that the blood of dragons courses through their veins. That claim may even be true in some cases - it is common knowledge that certain powerful dragons can take human form and even humanoid lovers, and it's difficult to prove that a given sorceror does not have a dragon ancestor.
Seems innocuous enough, except this one line is what got it in everyone's head that "Sorcerer powers always come from a magical ancestor." Of course additional WotC and Pathfinder fluff on the sorcerer afterward didn't help, but those things came about after this one line had already done its damage.


If you want to have sorcerers that work in a different way, you have to actively fight against this player perception. The biggest problem with worldbuilding in D&D is you often have to spend more time talking about what isn't true than what is. This is a very, very bad thing in a game that isn't supposed to have a default setting, and going halfway with the fluff just gives you the worst of both worlds.