Desire Is a Contract You Make to Be Unhappy
Desire is a contract you make with yourself to be unhappy until you get what you want. You start becoming disturbed because you want something, and then you work really hard to get that thing. You're miserable in the meantime, and then when you get that thing, you actually revert to the state you were in before you had that thing.
It's not like you get to some blissful peak level that you stay on. There's a delusion that there's something out there that will make me happy and fulfill forever. That is a complete delusion; no one thing seems to do that.
We can talk later about enlightenment, and that does seem to head in that direction of a permanent solution, but we're not gonna explore that just yet. We're just talking about common-sense happiness. There's no single permanent solution to it; rather, it is a process of understanding.
It is a process of self-discovery. It is a process of training yourself and seeing certain truths. If obtaining things were to permanently make us happy, then the cavemen would have been miserable, and we should all be deliriously happy right now.
So, obviously, net happiness per person is not going up. It might even be going down. Modernity probably brings more unhappiness than pastimes. So happiness is returning to that state where nothing is missing in this moment.