Luck

The 'Greatest Gen' earned their luck. As children they were aware of losing it. They suffered over its loss and fought for it, triumphed in gaining it, then squeezed it, the sweet orange of their adulthood and old age.

'Boomers' were born into it, expected it, found it to slip, rued not being able to hang onto it, and have been softened by expecting it.

X'ers have never really known it, but heard elders talk of it, thought they had been cheated of it, pretended to an affluence that substituted for it, and felt not one whit certain of it, despite declaring an ideological allegiance to it through either capitalism or a brittle neo-progressivism.

Those under 25, bewildered by what it means, still play around, surrounded by that form of it that doesn't realize itself before it's not there anymore.