Life in Dwarf Fortress was hard enough before the devs gave its denizens the ability to remember what had happened to them. After giving those dwarves the ability to remember their spouses being crushed by boulders, I'm pleased to report that the devs have softened up a little.
Now those memories get a tad less painful over time, and reflecting on them lets dwarves grow as individuals: "there are now little character arcs for the dwarves".
Those dwarves have update 0.44.11 to thank for their expanding memories, which also lets the player interact with the wider world via expeditions to "prosperous fortresses". You can read about that in more detail on the devblog, though I'm going to tell you about the memory stuff because it's way more interesting.
As explained in the patch notes, "this release should also improve the issues dwarves were having with negative thoughts, and they can also now experience permanent changes in their personalities and intellectual values due to events in their lives."
A similar experience can shape different dwarves in different ways, but it sounds like they'll usually become slightly better people. Here are more specifics from a devblog entry early last month:
"Memories will also change in nature after a year or two; the associated emotion will change to something less extreme, and as this happens, dwarves can undergo permanent changes to their personality facets and intellectual values. When this happens, it'll be indicated in the personality readout with a bright magenta clause that doesn't go away when the thought goes away, so you'll be able to catalog what has happened easily. It'll tell you which way the facet/value changed, as well as the event that caused the change and the year. For instance, a dwarf that was mortified after their clothes rotted off their body might later reflect on this incident with amusement and become slightly less interested in decorum and less bashful, while a different dwarf might react with unease remembering a similar event for the rest of their life, but also develop some empathy. Overall, that means there are now little character arcs for the dwarves, which should be pretty fun, though there's a lot more to do there."
The dev (either Tarn or Zach Adams) also mentioned that he was "planning on toning down the memories from seeing little corpse bits like teeth which can now traumatize people for the rest of their lives". Sure enough, the recent path notes state that they've "changed horror calculation from seeing a dead body". How considerate.
If the idea of shaping virtual dwarven personalities by deliberately traumatising them appeals as much to you as it does to me, you can download Dwarf Fortress for free from its website.