Perhaps we want most those things which are not within our grasp?
I think that is part of it, Francais. But also, that our capacity for certain treasured aspects of life - small joys, deep affections, trust and love, to name a few - can be killed if not nurtured. A cold childhood can raise a barren adult.
For a more self-induced regret, here is:
Days
Daughters of Time, the hypocritic Days,
Muffled and dumb like barefoot dervishes,
And marching single in an endless file,
Bring diadems and fagots in their hands.
To each they offer gifts after his will,
Bread, kingdoms, stars, and sky that holds them all.
I, in my pleachèd garden, watched the pomp,
Forgot my morning wishes, hastily
Took a few herbs and apples, and the Day
Turned and departed silent. I, too late,
Under her solemn fillet saw the scorn.
--Ralph Waldo Emerson
