Thich Nhat Hanh beautifully wrote in his narrative work, Old Path White Clouds:

Gautama entered even more deeply into meditation. He saw how countless worlds arose and fell, were created and destroyed. He saw how countless beings pass through countless births and death. He saw that these births and deaths were but outward appearances and not true reality, just as millions of waves rise and fall incessantly on the surface of the sea, while the sea itself is beyond birth and death. If the waves understood that they themselves were water, they would transcend birth and death and alive at true inner peace, overcoming all fear. This realization enabled Gautama to transcend the net of birth and death, and he smiled.(1)

If you are like me, you exclude the whole reincarnation bit in whatever form it may be (2). But the key here is that everything is passing away and so much new is coming to be.
Impermanence. Everything is constantly changing. Take a look at pictures from a decade ago – do you really think that you are that same person? If you do, not much has changed in your life. I barely feel connected to that ‘me’ because so much has changed. When you see the face of an old lover and realize that they no longer look like the person you remember. When you step out of bed and feel a kink in your back every morning and know that your body is wearing out. This is you changing.
Love changes. How many people fall out of love because of whatever reason? It’s idiotic to assume that love is that intoxicating rush into another’s arms to explore feelings that are unique to that particular relationship. Once every area in that relationship has been explored, then what? It must evolve or die.
Tastes change. Today, I could hardly listen to the teenage angst screamo music of my high school years. I now enjoy the flavors of wasabi and ginger, whereas a decade ago I was limited to ketchup and honey mustard exclusively.
Goals in life change. Beliefs change. Purpose changes as well.
Now all of this us back to the absurd – to the nihilistic pangs of existence. But look closer at impermanence.
The pain from the lost of a loved one – by heartbreak or death – starts to fade away with time. How could you go on with that pain as strong as ever? Addiction makes way for new habits with continuous effort and restructuring. A child grows into a beautiful adult. A seed turns to wheat and turns to bread and so on.
Impermanence, even though it makes everything seem pointless, allows life to continue. Desire glues us to the past, to what we cannot have, to what is also fading. How many ghosts have we chased to realize that the memory of a loved one is just that – a memory, a fading one at that. A seeming paradox arises – if nothing means anything, everything means everything. How much money would you pay for one breath? Not much unless it was your final one.
Value comes from the relations between subjects and objects. Subjects are always changing; objects are always changing; and relations between them are always changing. Why try to hold on to water? Let it go and smile at it falling from your hand. Sit and watch your child play. Love because the moment feels right. If you use your head too much, you’ll become to attached to your ideas and constructed identity. Live in the moment and experience freedom.
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(1) Thich Nhat Hanh. Old Path White Clouds. Paralax Press, 1991. pg. 157.
(2) Unless you have seen Jupiter Rising, in which case you could say there is a practical element to the idea as a genetic or atomic structuralism.