Generally, a character's dullness is equal to a viewer/reader's uncaringness. Riley, for example, is a BtVS character often slammed for being dull. But if a viewer steps into his head and tries to look at the story from his perspective - Riley's not dull. Tends to apply to most everyone.

I'm not familiar with "House", but I've definitely felt the Lana-infatuation you mention, and seen similar character-focused infatuations in fanfic and stories before. It's a pitfall of being a creator. Sometimes, folks get so enamored of a character that they lose the ability to soo how characters need to grow and change. (Because that's admitting to a flaws, and the infatuated person hates doing that.) Some writers just fall into that trap, and some start out that way on purpose. Subconsciously, anyway. (Smallville)