"Happiness" could be defined as just having what you define yourself to want, or having what you like.
But more and more "happiness" is defined as specifically the "emotion" of being happy and more and more "emotion" as implying an involuntary physiological response.
Thinking critically it makes no sense to prioritize a physiological response as my highest good. Even if I find it enjoyable there are things like learning, skill-building, and taking care of the interests of those around me and an interest in the well being of others in society and in the world that are more important than just enjoying a physiological response. In fact if I notice what makes me "happy" in terms of the physiological response I should endeavor to avoid getting too much of it if it is in relation to things that don't flatter these ends and I should endeavor to condition myself towards experiencing happiness at things that do flatter them. That way I can help guide my future behavior in a more productive and virtuous manner.
Haha just for fun, though. Seriously, if it were preferable, then by definition it must be causing happiness (at least in comparison to the available alternatives). Therefore, the two states preferring and unhappy can never coexist in the same mental phenomena. Does this win by default? I hope it doesn't.