Nostalgia for samsara happens in different ways. Maybe the simplest, and one we all may experience daily, is a nostalgia for old patterns that have weakened or identification has gone out of.
I notice this one when I find myself in a situation that used to trigger a certain pattern, and the pattern is either not there or just a ghost of itself with no hooks anymore. There is a sense that I should go into the old pattern, that this pattern inherently goes with the situation, that it is somehow wrong to not go into it as I used to. The old familiar habitual pattern is so strongly associated with the situation that something feels off if it is not there. Yet, it is also not possible to go into the old pattern in the same way as before. It does not have the same hooks anymore. It doesn’t have the same juice anymore.
And as time goes by, this one too falls away.