I am not a happy person. There are things that do make me experience joy. But joy is a fleeting emotion, like a very long sneeze. A lot of the time what I feel is, interested. Or I feel melancholy. And I also frequently feel tenderness, annoyance, confusion, fear, hopelessness. It doesn't all add up to anything I would call happiness. But what I'm thinking is, is that so terrible?I know a physicist who loves his work. People mistake his constant focus and thought with unhappiness. But he's not unhappy. He's busy. I bet when he dies, there will be a book on his chest. Happiness is a treadmill of a goal for people who are not happy by nature. Being an unhappy person does not mean you must be sad or dark. You can be interested, instead of happy. You can be fascinated instead of happy....But holes are interesting things. As it happens, we human beings are able to live just fine with many holes of many sizes and shapes. Pleasure, love, compassion, fulfillment; these things do not leak out of holes of any size. So we can be filled with holes and loss and wide expanses of unhealed geography—and we can also be excited by life and in love and content at the exact same moment.
For me, the closest correlate to the generic "happiness" is the feeling of being fully immersed in an experience, not taking it for granted.