Bubbles

I am in a little bubble. Sic.
And so are you.
Bubbles, thin, thick, transparent,  non-transparent,,,

Generations may be enhanced by giant bubbles. (What is generation and what is bubble? - never mind.)
These generation bubbles aren't congregations and there's no team spirit within.  We don't know each other. When one from my generation passed (Terry Pratchett March 2015) it became clear he was well known as a kind of fantasy author. But I hadn't heard of him neither read anything of him!

All bubbles are rising.
Pushed up by younger giant bubbles.
When high enough the bubbles burst - one by one.
The journey is completed.