At each stage of your life, there are one to a few things about which you think “If only I had this/these, everything would be great”.
Some things you go on to get, and some things you don’t.
Of the ones you do, some bring a short term boost of happiness which eventually fades away, and some, contrary to your expectations, are either neutral or surprisingly actually cause unhappiness.
We can’t not wish for our futures. It’s engrained in us as the result of thousands of years of evolution, and it’s what keeps us going.
But whatever happiness we believe having a few arbitrary things in the future will bring, we actually already have. We’re just wired to not be able to see it without deeper reflection.