I think a lot of us have, at one point, taken medication that has made us too stable (i.e., flat). Or we were so used to having unstable, extreme mood swings that we didn't know what regular everyday emotion was. I mean, how can you know what "happy" feels like when you're euphoric from mania, or "sad" when you're depressed/mixed? And how can we know what "happy" and "sad" feel like when we're flat?

Those feelings of euphoria and depression are two extremes... so it's kind of hard to know what regular happy/sad emotions feel like. And not feeling anything means we're not used to feeling "happy" or "sad." But when we finally do feel regular emotion, we are overwhelmed by it and therefore have an exaggerated reaction compared to the average person. We just don't know how to handle it well, hence the crying etc.. Just my two cents, though.