Trope-a-Day: You Can't Go Home Again

You Can’t Go Home Again: A consequence of lighthugger travel and the ensuing time dilation for ephemerals; or people from ephemeral societies, rather, since it’s the high cultural delta of the society you left that causes the problem.

Also, more rarely, what happens to people left off-world at the time of an Apocalypse How or Gone Horribly Right.