Wouldn’t it be nice if we were older
Then we wouldn’t have to wait so long?
And wouldn’t it be nice to live together
In the kind of world where we belong?You know it’s gonna make it that much better
When we can say goodnight and stay togetherWouldn’t it be nice if we could wake up
In the morning when the day is new?
And after having spent the day together
Hold each other close the whole night through?Happy times together we’ve been spending
I wish that every kiss was neverending
Oh wouldn’t it be nice?Maybe if we think and wish and hope and pray it might come true
Baby then there wouldn’t be a single thing we couldn’t do
We could be married (we could be married)
And then we’d be happy (and then we’d be happy)
Oh wouldn’t it be nice?You know it seems the more we talk about it
It only makes it worse to live without it
But lets talk about it
Oh wouldn’t it be nice?Good night my baby
Sleep tight my baby
From What was not, is not, and will never be:
We long for what was and is impossible.
Surface Your Real Self 
I think we long for what the song describes because we evolved in small groups that lived, played, ate and slept together. Our modern way of living keeps taking as away from our natural state, and we can sense that disconnection from our true selves in our longing for something better.
The neuro-scientists can look in their fancy machines and tell us about our DNA, but that is just ‘physical’ science. The brain also produces feelings and sensations that cannot be seen through a microscope. To understand what they say to us we need to be able to experience them directly. Only then will neuro-scientists understand the spiritual side (pure love) of human functioning.