I'm usually so upbeat I guess I need the occasional downs to release my frustrations away.
I dunno, it seems odd to imply this, but I quite like the days when I get to feel low, I think I try so hard to cheer other people up, a sign of being low is a sign that my body wants me to stop and pay attention to it; indulge it for a while. After all, we all need a little me time, and I don't assign myself a lot of it.