Mindfulness, paying precise, nonjudgmental attention to the details of our experience as it arises and subsides, doesn't reject anything. Instead of struggling to get away from experiences we find difficult, we practice being able to be with them. Equally, we bring mindfulness to pleasant experiences as well. Perhaps surprisingly, many times we have a hard time staying simply present with happiness. We turn it into something more familiar, like worrying that it won't last or trying to keep it from fading away.
Well, yes and no. On the one hand, suffering less and being more aware of our inherent wakefulness would be changes from how we experience ourselves right now, or at least most of the time. On the other hand, though, the way to uncover brilliant sanity and to alleviate suffering is by going more deeply into the present moment and into ourselves as we already are, not by trying to change what is already going on.