system
Given the following post, respond as if you're commenting on Reddit:
human
[Warhammer 40k] What is the least Grimdark part of 40k currently?

In the grim future where there is only war, what is the least grimdark part of the universe in the modern age of 40k? I do not mean what was once not so dark, I mean currently what is the least not dark. This can be a person, group, planet, item, food, city, animal anything. As long as it is the least grimdark, it does not have to be bright and happy, just not as soul crushingly awful as most of the galaxy in current 40k.
gpt
Specific example: The Orders Hospitaller is a division of the Adeptus Sororitas that is dedicated to providing medical services to all (loyal and human) who need it. They're often attached to armies, where they're the most compassion a soldier can receive, and deploy to disaster areas or war zones to provide emergency care and relief. 

On the big scale, the galaxy and Imperium are *systematically* awful; the constant war, oppressive rule, ceaseless threats, massive tithe burdens, and uncaring bureaucracy are terrible. No doubt about that. Genocide, oppression, a universal mindset of superstition and xenophobia, billions dying a day as armies of billions more are raised, and - worst of all - it may all be necessary.

But lots of people don't live that day to day. Most don't even know that space travel is possible, let alone keep up with the horror of current events. Their lives are much, much smaller than that. Little moments and little people are where you find the least grimdarkness.

Shopkeepers who believe in an honest deal and are looking forward to closing up for the night so they can play with their kids. A squad of guardsmen wordlessly pass around a bottle of hooch they found in a ruined building. A hive dweller surprises his wife with a special meal he's been saving up for - real meat and vegetables. Old friends run into each other on the street and grab a caff to catch up. Void dwellers solemnly paint wards on their skin in preparation for a funeral. A battle-hardened ganger in the underhive, who's never seen sunlight and has fought to stay alive every day since birth, cracks dirty jokes with their gang buddies. Clergy in the Imperial Cult - between litanies of hate for the xenos, mutant, and witch - work in soup kitchens and alms houses. 

A Company of Space Marines give their lives guarding an evacuation of a strategically useless civilian city. A merchant captain sells his shipment of wheat well below cost to alleviate a famine. A planetary governor tirelessly pushes through reforms to provide for the most destitute of her people.

Even the most paranoid, hateful, overburdened (even if justifiably so) Inquisitors occasionally have to take a day to just lock the door, turn off the vox, soak in a hot bath, read a book, and go to bed early.

The Imperium is inhumane, but it's still a *human* empire, and in between all of the hate and fear and death and poverty are human beings doing all the other things humans do: making friends, building families, having sex, trying to grab the bar tab from each other, putting little kids on their shoulders, gossiping about neighbors, and just sitting quietly together for a few minutes.