“The mind is its own place, and in itself can make a heaven of hell, a hell of heaven..”
― John Milton, Paradise Lost
So it is said to enjoy lasting happiness we need to give up hankering and lamenting.
“As long as we are in material existence, we lament for the losses in our life and hanker for that which we do not have. A self-realized person is joyful because he is free from material lamentation and hankering.”
So easy to say so hard to do as it is the nature of the mind to do so. Here is an example.
There is a short cut I have taken through Moundsville more than a hundred times. It involves a jag on 4th Street then a left by a church. The other day that street was closed so I had to go to the next one to cut over. On the way back I turned down that same street and had the realization that if I had gone to the normal street there is a stop sign there then another at 4th Street while the new route only had the stop sign at 4th.
Which meant that every time thereafter I take that route I can miss a stop sign and I take it a lot. So it should have been a moment of joy but my mind turned it into a lamentation by thinking how many times I had taken the old route and made an unnecessary stop.
Nothing changed but my mind made a negative reaction to what should have been a happiness. Such is the power of consciousness.
“One who is thus transcendentally situated at once realizes the Supreme Brahman and becomes fully joyful. He never laments or desires to have anything. He is equally disposed toward every living entity. In that state he attains pure devotional service unto Me.”
Bhagavad Gita 18.54