I was recently asked this question and here is my answer:

Interesting question.

My sense is that the “pursuit of happiness” (as we currently understand that word) is an illusion.

A pursuit implies that we don’t yet have whatever it is we are chasing.

This striving for something we don’t have or treating where we are now as somehow being in preparation for something else, means that our focus is continually on the future.

The risk then is that if you do somehow manage to get to the promised land, your focus may well be on some distance horizon, and you may not be able to fully enjoy it.

Alan Watts explores this theme of living for somewhere you aren’t:

“There is no use planning for a future, which when you get to it and it becomes the present, you won’t be there. You will be living in some other future that hasn’t yet arrived. And so, in this way, one is never able to inherit and enjoy the fruits of one’s actions. You can’t live at all unless you can live fully now.”