My belief is that it's something within people that connects us to others and to our own motivations. I've heard some say that it's actually an aspect of reality outside of people, but I don't really believe that feelings would exist without people to experience them. I feel like you need people to have feelings... and that they aren't a part of reality itself, but are the most important pattern for us in a more intricate and complex reality that includes people.
Also, do you distinguish between "higher" and "lower" emotions? For instance, higher ones being things such as charity, politeness, and a sense of pride. Lower ones could be things like lust, anger, and fear. I tend to feel good about the higher ones, and avoid the lower ones as much as possible.