last gasps:

One is sort of making it safe to re-experience things, as part of how meditation works—eventually a re-experiencing is sort of the "final burning off of the (conditioning of the) thing." So often a person will re-experience at least a shadow of old, bad things, over and over again, until not again—things that they thought were long resolved, in the course of a great deal of meditation. (One trap is thinking that one is not making progress, because this thing has come up more than one time. It is progress! That’s just how the mind works.)

But there’s another thing that’s more problematic: If a person was crushing down a bunch of stuff, let’s say they then stop crushing. But say they haven’t fully worked through the thing(s) under the crushing. If something happens in the world to trigger them, around those now uncrushed things, like they see their old girlfriend or whatever, they might have a more extreme, more impulsive, more destructive reaction, in that particular case, than if they hadn’t ever meditated:

Behavior, belief or the very seeming of the world, and its attendant justification, will become live again, seem like the right thing to think/see/do.

And then they’ll/you’ll be in old destructive patterns, transiently, as bad or even worse than when those initial patterns were getting laid down. And then it’s maybe doubly regretful because this "last gasp" can go by fast. It can be embarrassing, especially if one is a self-styled advanced meditator. And if only you’d gotten to that old stuff, metabolized it, before being triggered. One just has to be as careful and meta-careful and meta-meta-careful and responsible with and around other people as one can be, and to make amends and reparations, if warranted, in a way that actually delivers, that takes into account all this. Not your fault, yet no excuse, all at once; it’ll be ok, but you can’t morally rely on that, etc.

Last gasps can be discouraging ("I thought I had made progress on this, but it seems like I've made no progress on this! It's been ready to blow all along!"). But, actually, you have been making progress all along: The mind can be very digital and all-or-nothing, sometimes. That is, "15%" progress can still be "100% problematic reaction." "85% progress" can still be "100% problematic reaction." "99% progress" can still be "100% problematic reaction."

And, but, finally, "100% progress" yields, sort of suddenly, almost digitally, "0% problematic reaction."

Sometimes "99% progress" can mean, unfortunately, "120% [sic] problematic reaction," because all "compensatory layering" or "counteractive layering" has been removed, in preparation for integration, metabolization, harmonization (i.e. the drop to 0% problematic reaction). Thus, "last gasp," "worse than ever."

But if one realizes that this can be a thing, one can be more careful about the possibility of last gasps (though usually one shouldn't avoid triggering contexts entirely/completely--they help with processing), and one can be less discouraged (or not discouraged) if a last gasp still unfortunately occurs, in a problematic way.