As an extreme example, consider value system of a heroin addict, for instance. He or she values heroin above all. You might say his value system is inferior to yours, but how would you defend that statement? Speaking from utilitarian point of view, it's not necessarily that a heroin addict decreases society's happiness or pleasure, if he uses it as a constructive stimuli.
Speaking from a physiological point of view, we are not much different from heroin addicts. My opinion is that value systems are psychological routes by which we can get an endogenous high. Our brains have built a series of quests for us to accomplish, after which they reward us with various pleasurable chemicals.
Some people get high watching Fox News, some people get high debating philosophy, some people get high from heroin. The value of each activity is (non-verbally) agreed upon, by spending time on that activity and hanging around people who spend their time on the activity.