We don’t even own ourselves. Our bodies get sick, they get old, they die. We don’t own shit. We just inhabit our bodies, temporarily. We don’t own a house. It’s some bricks on the ground. The ground might shake or be flooded or get taken away by some hostile tribe. Ownership of anything is an illusion. Using a thing to validate your self worth or lack thereof (look at my house, I’m special!), or a person (he thinks I’m great!) is bound to yield regret.
Happiness, as professed everywhere else, is the moment, the state of sharing a space, of having the opportunity to have an experience. Nothing more, nothing less.