The Forty Foot Leap
You can jump way the hell up into the air during your desperation attack, but you somehow cant cross a gap in the floorboards...
OH what a comeback! (Limit Break Rule)
As a villain, kicking the hero's ass is apparently the best way to make sure they get damn well pissed off enough to turn the tables on you. Prepare for the forty foot leap. Don't forget to further the pro-wrestling cliche by standing still as you get smacked silly while the player frantically mashes R1.
It's gotta be the hair... (a.k.a. Rule of Male Significance)
You can recognize characters male characters that are significant to the plot by their wild, cumbersome hairstyles. Men with average-length, plain hairstyles are either random townspeople or goons that you will defeat in the hundreds in simple random encounters.
But I'm a Dapper Dan man!
These cumbersome hairstyles are maintained due to the ready amount of hair products available in all locations, including dungeons, ice deserts, volcanoes, outer space, prehistoric times, and secret ancient continents.
Dude looks like a lady
Androgenous males are no doubt the most dangerous damn things you'll come across. The more flamboyant, the deadlier. Apparently Panic! At The Disco changed their stage act and no longer requires the need of these characters - understandably, they're quite pissed. This world is not enough, after all.
OMFG Zerg rush!
You can tell you've entered the final plot arc when the OMFG Zerg rush! occurs. The villain unleashes a horde of monsters pointed at the planet. Or a ridiculously large fleet of airships. Or a natural disaster. Or a collossal sleeping giant. While your airship will most certainly collide with these nasties, they dont amount to much more than an impressive aerial FMV of impending danger, which leads us to out next rule...
Nah, it's cool. We'll be here when you get back.
The OMFG Zerg rush really isn't that significant, as is any other non-instantaneous catastrophe. You can take the next 50 hours to level up, do bonus quests, pimp your weapons. It's all good. The OMFG Zerg rush is frozen in time, waiting for you to be as ready as possible to clean house.
So THAT'S what it does...
The useless weapon you either start the game with or acquire after the first boss fight is the most powerful weapon of it's kind. You just need to:
1) wait until the world is destroyed and it's "true purpose is revealed"
2) wait until your surrogate father figure is murdered by the lead villain, unleashing your "true rage" within the weapon
3) wait until your character's stats fulfill the arbitrary mathematics that dictate the weapon's usefulness
With Friends like you...(Zegram Rule)
Betraying the party one or multiple times and facilitating the demise of the world is pretty well forgiveable, I mean, you're sorry after all, right?
99 bottles of Ether on the wall...
Even if there's space for more tents, swords, log cabins, robot accessories in the party bag, i'm sorry, there's just doesn't seem to be a place for that hundredth potion...
'Cause this is my United States of Whatever!
There's always a flippant character that pretends not to care about anything. Be patient. He's suffered a tragic loss in the past and this is "just how he deals with things".
Charlie, how'd your Angels get down like that?
A petite girl with a supermodel figure and no trace of muscle can totally own a hulking thug in a fistfight. Girls can do anything boys can do!
Charlie, how'd your Angels get down like that? (Part II)
Aforementioned petite girl will look rather immaculate after beating down scores of hulking thugs, hair and makeup in place.
He wasn't there when we got here!
Due to the fact that you cannot see most random encounters on the map, you can be ambushed by pretty much anything. Including giant iron golems in tiny prison cells, or hordes of zombies in the storeroom of a mansion.
Tyler Durden's Corollary
You will wear one set of clothing, it will last you the entire game. Except when you have to infiltrate an enemy base or sing in the opera.
Everything I know about women I learned from games...
The best way to make a girl like you is to be a complete asshole. If you act like a decent human being, she'll blow you off and wont give you the time of day until you save her life, which you'll undoubtedly have to do at least once.
Fucking Nerd Translator Rule
The guy who translated your game from original Japanese has an unhealthy obsession with Star Wars/Lord of the Rings/Star Trek/The Matrix/The Beatles/Led Zepplin/Monty Python and thinks it's really funny to insert periodic references to these things in the game's dialogue.
David Blaine's world of shame
Pretty much everyone can hold their breath underwater indefinitely or for some record breaking amount of time, like twenty minutes. They can also vigorously swim and fight while doing so.
You can piece together any nonsensical plot by simply falling back on the fact that the lead villain is certifiably insane.
No quarter for the Batshit Crazy
Being seekers of justice, the heroes see no harm in killing the hell out of a Batshit Crazy villain for acting out his/her delusions. After all, being certifiably insane isn't a valid legal defense. Oh, wait. It is.