This Index Means Trouble

This is an index of people, places, things, and tropes that will almost always lead to conflict, whether it be a Flame War, Bar Brawl, Blast Out, or even a full scale actual war.

These Stock Characters and people are looking for trouble.

Angry Mob: a bunch of people just waiting to have a fight
Blood Knight: someone who wants to fight at any cost.
Boisterous Bruiser: someone who has no problem with fighting and is capable of doing so
Bounty Hunter: He (or she) is almost always around for a reason... and that reason or the bounty hunters' zeal in going after it will ruin your establishment or your day...
Death Seeker: someone who wants to die at any cost, but not necessarily by their own hand
The Fundamentalist: someone who wants you to believe and practice their belief, and only their belief
Heteronormative Crusader: if you're anything but straight, this person will ruin your day at best and your life at worst.
Girl with Psycho Weapon: A living Chekhov's Gun. Even though the weapon is rarely a gun.
Knight Templar: When The Fundamentalist goes past screaming tirades into physical violence.
Jerkass: someone who, through actions or attitude, can easily provoke a fight
Leeroy Jenkins: someone who charges into a situation and starts a chaotic, unplanned fight
Lower Class Lout: a stereotypical someone from a culture that celebrates violence and fighting
Powder Keg Crowd: Slightly different from the Angry Mob, but can become it with just the slightest spark...
Organized criminals in general: When the Gang-Bangers, The Mafia, The Mafiya, Murder, Inc., The Triads and the Tongs, and/or the Yakuza (or even just The Family for the Whole Family) show up, you know there's going to be trouble. And if they're all converging on one location, it's probably going to be a Blast Out at best.
Troll: Starting fights is their raison d'etre, and forms of this behavior do exist off the Internet
Violent Glaswegian: another stereotypical someone who likes fighting and violence

This place is just bad news.

Bad Guy Bar: a place where troublemakers of various sorts congregate
Diners: because why just have dinner when you can have a fight with dinner?
The combination of Crapsack World and Empathic Environment: everyone feels like crap and wants to take it out on someone else
Wretched Hive: a lot of very bad people centered in one very bad place.
Vice City: a lot of very bad people and a lot of money circulating around one place.

That thing looks dangerous.

Arab-Israeli Conflict: No one can touch this without starting a fight.
Berserk Button: Don't Touch It, You Idiot!!
Any Chekhov's Gun: why yes, they will be fired
Hate Plague: If someone (or some group of people) contracts this, fighting will ensue.
Happy Fun Ball: Because someone will discover that it is nowhere near as innocent as it looks.
Misplaced Nationalism: Whenever this gets invoked online or offline, run for your life. Sometimes, literally.
Politics: There is a reason why it's banned or heavily restricted as a topic of discussion pretty much anywhere that it's not the only topic of discussion. Religion is very, very close to it. Combining the two will almost always lead to fights.
The Deadliest Mushroom / Nuke'Em /nuclear weapons in general: if one ever gets set off, war (and The End of the World as We Know It) will ensue
The Plague: A devastating disease can drive societies to chaos as people left and right drop like flies.
Post-Peak Oil: Restricting modern society from one of the most, if not the most important substance can lead to a complete breakdown and collapse of it.
Sealed Evil in a Can: Probably one of the very first examples. Opening it is not a good idea. And yet of course someone will...

Why did you have to invoke that?:

Any of the "All X are Y" tropes. This includes such tropes as All Gays Are Pedophiles - stating straight belief in them around anyone who is part of the X group but not the Y group will almost always start a fight (or at least lead to very uncomfortable silence)
Axes At School: Unless it's a school of warfare (and even then sometimes) bringing a weapon into school will cause major trouble.
Commie Nazis: Conflate "Commies" and "Nazis" to a Russian, get anything from slapped to a No-Holds-Barred Beatdown.
Guns in Church: In some settings, and in MOST settings in Real Life, openly carrying or especially brandishing a firearm will lead to an arrest, a fight, or sudden death.
Murder Is the Best Solution: If someone decides to invoke this, of course there will be conflict.
Stay in the Kitchen: Invoking this to most women who don't believe in it will start a fight
Strawman Political: Invoking this will almost always start a fight
Violence Is the Only Option: Obviously, if someone thinks this, there is gong to be violence.