In general, it's quite easy to accidentally put people down, especially when your assistant can read your mind or face, as shown in the fourth case of Phoenix Wright: Ace Attorney if you answer "Yeah, you're useless".
Maya: I know... I'm no good for anything, am I, Nick? If I can't call my sister, I might as well not be here, right? Phoenix: Um, well, actually... [thinking] (You don't know law, you don't have any trial experience or techniques... Yeah, you're pretty much useless... but I can't say that!) Maya: It's okay Nick. You don't have to say anything. Your face said it for you. Phoenix:[thinking] (Whoops!)
In the third case of Phoenix Wright: Ace Attorney: Justice for AllAcro turns out to have killed Russell Berry accidentally while trying to kill Russell's daughter Regina because she accidentally put Acro's brother Bat in a coma and is so naïve that she doesn't even understand what she's done. At the end of the case, Regina asks if Acro is going to come after her. The "correct" answer is to say "No," and to show her some evidence, but's there's no real reason you can't say "Of course he is!" and send her off in tears.
Halfway through the case, you'll run into Franziska during the second investigation phase. For every irrelevant piece of evidence you present to her, she whips Maya. You can do this as many times as you like without any repercussion.
In Ace Attorney Investigations: Miles Edgeworth Case 5, you run into the Steel Samurai, who reveals himself to be Larry Butz. If you present the wrong evidence to him during the one investigation phase that lets you talk to him, Larry refuses to look at your evidence because he's too busy staring atFranziska. Franziska promptly offers to "sear her image into his mind for eternity" by sending him on a "Whippity-Whip-Trip" into unconsciousness. This is probably the one time in which presenting wrong evidence in an investigation phase can be pretty satisfying... and hilarious.
The first game's fourth case had two examples of this with the Butt Monkeys of choice being Lotta and/or Larry. At some point, Gumshoe will offer you either a dog (Missile), a fishing rod or a metal detector to fish for Gourdy to find key evidence for your case. The correct choice would be the metal detector, but the two other options can lead to this. For Lotta, the player can take the fishing pole which Maya will use in the lake to fish for Gourdy, only to trip and fall, causing Lotta's cameras to react and waste more (very expensive) rolls of film than you already wasted earlier in the case. For Larry, the player can take Missile who will react automatically to the aroma of Larry's Samurai dogs the minute you get into the park, let alone the crime scene, causing the aptly-named poochy to run like a missile and chow down on all of Larry's hotdogs, making him lose his (at this point, already doomed) business. For added butthurt, you can also show Missile to Larry after the puppy ate his entire revenue.
Lotta still gets misfortune even if you don't get the fishing rod. If you don't get it, Maya sneezes, setting off the camera anyways.
Another minor example from the same case: When you first start the case, Edgeworth refuses to let you defend him. After running around and gathering evidence for a while, Phoenix and Maya return to the Detention Center to speak with Edgeworth again. At this point, Edgeworth relents and asks Phoenix to defend him. The game continues regardless of your choice, but you can always choose to troll Edgeworth and tell him "Sorry, you missed your chance!", scaring him half to death and prompting both him and Maya to yell at you for your cruel sense of humour.
In the third game's second case, examining the ceremonial sword will prompt Maya to strike Phoenix on the head with it. You can keep examining it, letting Maya repeatedly strike Phoenix on the head with it. One can only wonder how hard that head is...
The game Sprung gives the player character mace which has absolutely no purpose within the game except for the player to spray it in people's eyes and see them cry. Becky also gets the equipment necessary to set somebody on fire (this does result in a game over).
Just playingLong Live the Queen is cruel, because your cute little magical girl princess is going to die an awful lot of horrible deaths. However, you can also use her to commit acts of gleeful wickedness against other characters. Among other things, you can force a woman into marriage, abuse the servants, ramp up punishments in hopes of discouraging assassination attempts, execute people at random, reduce a woman to tears by blaming her for her daughter's death, and sacrifice your thirteen-year-old cousin to a kraken. The game actually has, alongside the various in-game stat meters shown to you, a hidden Cruelty stat which, if sufficiently increased, allows you to do even more awful acts, up to and including murdering your own father.
In Dangan Ronpa and Super Dangan Ronpa 2, there is an additional mode that works like a dating sim. At certain points during those modes, the students ended up talking to the main character about their pain, fears, frustrations, vulnerabilities and insecurities all on display, while the only available command involves agreeing or disagreeing with these internal reflections. Depending on the context, it's possible to make the main character of both of those games say some incredibly mean things to the other students.