The prices don't increase if they don't see you murder their friends. At least that's my personal experience on it.
Today in Payday I casually walked into a bank and unloaded my MG43 into the crowd. Just saying this means I'll be on so many watchlists right now.
Cramming a 4 by 4 meter cage full of innocent slimes, then realising a terrifying angry sludge mutant into it and laughing at their terrified faces as they are eaten.
I killed an entire family in just cause 3 (husband, wife, and someone in the back, i think it was a kid) by attaching a wire to their car and off the bridge into the ocean and i watched them get out struggle to survive and then slowly die.
Actually, now follows the most cruel thing I've ever done in video games. The game in question was Open Transport Tycoon Deluxe, which is basically an open source TTD with multiplayer compatibility. I was playing with a couple of friends. One of them was doing REALLY REALLY well with passenger trains though. So naturally, because it was a friendly match between friendly people, we tried to sabotage him. What we ended up doing was setting up crash-blocks. They consisted of a truck depot, and a truck stop at either side of the rails. What you then did was buy trucks. A whole lot of trucks. So many trucks on those 3 tiles of road that it was just one big line of them. And then you waited for the train. You saw it come closer. You knew you would be the cause of hundreds of dead passengers. You did not care. Impact! Trucks destroyed, trains derailed, people dead or dying! A horrible accident! All to get rid of the competition. But it did not stop the other company. They just covered it up, fixed the rails, and sent another train. So a new fleet of trucks was bought and deployed. The rail was once more blocked. The new train leaves the station, thundering towards the blockade. But it does not slow down. It maintains speed as it comes closer. History is doomed to repeat itself...
When playing UO there was a guild war between 2 guilds, because my defenseless bard (we were neutral) was attempted to be murdered (by the good guys, guess what.) Later, my other char came across one of them, his unbelievably expensive and unique mount having been killed, which was forbidden according to the war rules and would likely have had huge consequences. Since my Character was one of the few skilled in Forensics, he asked me to create a letter of proof who killed it. I did. Then I placed it on the ground and field by field, I "hopped" it over to the next trashbin and threw it away, then told him a warm greeting from my poor bard.
Black&White, my tiger liked people, it helped them out watering the crops, healed them, placed materials for buildings, amused them, made diciples as necessary, fed the worshippers, didn't poop near the cities and was completely heartbroken every time people were afraid of it, which was quite often because it was only allowed to feed from the youngest in the creche. It belived us to be good, and while it was nearly maxed out in that stat, I was only using this immense worshipping that it made possible to wage war against everything and had long since maxed out the evil line of things.
Actually I just remembered something I did. Anarchy Online. I was a Monk-class character. On bosses, I would use nothing but a weapon until everyone was dead, then fucked the boss up with mah skills.
Not really a cruel person by nature so this one was more of an accident but ... Playing Classic mode Fire Emblem: Awakening, mistook Lissa for another unit and put her in the path of a bunch of Wyvern Riders ... Chapter 10. Kind of just stared at the screen for about 5 minutes afterward trying to process what I'd done.
In rimworld, you can do a lot of things to people... like operations to remove infected member or replace their destroyed jaw... But you can also capture people who are trying to raid you and you can make your doctor train on them... or take organs to sell them/use it for one of your own guy. One time I had remove a lung and a kidney of a prisoner... after what I started to cut his legs but I failed (somehow) so he died. After that I was actually feeling guilty so I reloaded my safe files and I let him go... And never I did that again. (I try to recruit them or I release them now) Well... except that time when one of my guy had a kidney destroyed during a fight... I actually replaced it with the one of a prisoner but still... I let him go after that. He is still lucky... he attacked me, I beat him... I heal him and he is free with just a missing kidney... ... But even with that, I still feel guilty. :s
Set up a successful slave/organ trade business in Rimworld. As a history student, I should have noticed earlier that my prisoner area looked suspiciously like a concentration camp. Yes, I still feel bad about this. Based the majority of my cash crop production on the labor of political prisoners in Tropico 4. Transformed a village into a dystopian concrete nightmare complete with smoking factory chimneys, adverts and political propaganda everywhere in Minecraft. The sad part: that was in singleplayer. Nuked natives in Empire Earth 2 because they were in the way. Drunkenly dropped a JDAM on civilians on Battlefield 2: Project Reality Put the entire middle east to the torch in Medieval 2: Total War. I wasn't even on a crusade. Did not marry Penny. Dd not marry Shane. Gunned down hundreds, if not thousands of regular people in GTA: Vice City just to see if I could. Nuked everything in several games. Ate a couple of pink cakes in front of Haley and then gifted her trash. ....are you convinced I am evil or do you need more?
Well as long as you have some form of barter system in place ... I loaded ... which was admittedly still pretty painful since it was Lunatic+ Difficulty.
I just remembered. In 1602 A.D. I blocked the port for one of the computer players so they couldn't trade. It wasn't long before they ran out of supplies (like food) because they couldn't trade or bring in anything from their smaller settlements. Their island fell apart. I don't think I had a reason to do it.