Well, I've learned how to not act in real life.
....
That's pretty much it.

I learned that cell phones can be used for cheatcodes

I've learned that "sv_cheats 1" followed by "noclip" in console can get you out of some serious situations.

I learned the bulk of my knowledge of the Vietnamese war from playing Battlefield: Vietnam ( a game which I feel guilty when I play)
I learned that the philosophies of Political innovators such as Voltaire and Hobbes apply to today's society by playing Counter Strike Source Zombie mod (probably one of the most intense zombie game I have ever played)
I also learned teamwork from the game as well and how proper communication can determine the difference between life and death
I learned tactics from Battlefield

Oops, my bad
Didn't read carefully

I have learned a sword is more effective then a AKA-47

I learned that curry gives you fire powers

*Twitchtwitch*
HAREVESTMOONMAGICALMELODYHAREVESTMOONMAGICALMELODYHAREVESTMOONMAGICALMELODY
okay, I'm good now.

SSBB.
Here's an obscure one:
I learned that green pens can help you go back in time.

Who says? My first list was just naming off random things from TF2. People can guess if they want, but I think this is just more to be silly. After all, some things are a bit to obscure to guess, and some things are tropes found in tons and tons of games. As for your game...Hmm...not sure, actually. You've got me stumped.
L4D2!

Super Smash Bros. Brawl! (Ninjaed by Brawler! *Shakes Fist*)

I learned that you can repel nearly 10 full grown adults at once buy swinging something in front of you.

...
BAH!
/Buckdida slaps himself with a fish!

Also:
I learned that metal shields with defend you from anything from the front...just don't let them get behind you.

Mario

I learned that a giant thunder lizard can give you the ability to turn injured foes into trading cards

Final Fantasy 8

I learned that one soldier can defeat an entire alien invasion by himself.

Halo series

I've learned that giving weapons to intelligent farmer's little helpers tend to be chaotic and fun at the same time

I learned that if you're good, you get a halo, blonde hair and flowers sprout wherever you step! But if you're evil, you get horns, green skin, and everything dies wherever you step!

Fable

I learned that the only way to truly defeat your arch enemy is to go back in time and abort their birth as they scream for you to stop, over and over again. Also praying helps...

I learned that 1940s comic/pop-culture makes for a great and creepy shooter game.

Too obvious? Oh welllll

wolfenstein and nazi zombies!

Bixlow...is that game...Earthbound? I haven't a clue to be honest...

I learned that I can destroy or save a town for a few bottle-caps!

Not a clue.

I learned that it's dangerous to go alone.

Legend of Zelda: The creepy old man in a Cave

I have learned that a green midget with a dagger is more dangerous than any boss.

Erm, LoZ: Wind Waker?

I learned that Kittens and puppies can dance a mean disco.

Warioware: Smooth Moves (I meant the TonBerries in Final Fantasy)

I learned that enemies are sometimes invincible, yet they get ordered around by a non-invincible guy. (I know it is a broad one, except it is something i have learned)

Any game with some level of hypnosis or mind control
I learned that money DOES grow on trees.

Animal Crossing if you get VERY lucky.

I learned that the Crazy impossible Boss of one place is the normal enemy of another.
I learned that when you start a quest to do something, you tend to start where the weakest opponents roam.

Lost Planet for the first one, and just about any MMORPG for the second.

I learned that combining a tribal shield and a buckler with a spike on it can get you a pair of metal plated boots.

Ohhhhhhhhhhhhhhhhhblivion?

I learned that "BAAAAAAAAAAAAAAH" is a legitimate form of communication.
(Meh, I can't come up with any good ones)

I have no idea what Teh Brawler's is, so I know nothing else but to skip it maybe?

I learned that if you combine a cheese wedge with a cheese wheel, you will get a Potion of Fire Resistance.

That's Oblivion.
(Mine was Rayman: Raving Rabbids, btw)
I learned that cats have the ability to make you younger.

Yes.

@TB: Blinx?

I learned that charging my beam saber in public is considered a 'rude gesture'
also that saving the game is as easy as going to the bathroom

Dead Rising!


Nope. TF2.
Chargin' Targe+Razorback=Gunboats.
They updated the crafting system, dontcha know?

I learned that zombies HATE...

Garden Gnomes.
And
Clowns with squeaky shoes.

Team Fortress 2, I believe?

I learned that the best weapon to give a guy who's about to save the world is a crowbar.

Nope. Time Hollow.

Enty: Half-life.

I learned that it's possible to feel asleep.

I've recognised since you put this up, but I had to look through a lot of AVGN videos until I found this!

the answer is metal gear for the NES!

I learned that EAVRYTHING KILLS YOU!

*speedy things goes in, speedy thing comes out* :3

Is that a Portal quote?

I learned that killing someone will give you their ability.

Megaman
I learned that people die when you send them into battle. Especially if you're low on vulneraries. (Yes, I know that gave it away, but it was too vague otherwise)

Fire.
Emblem.

I've learned that using peas as ammo on zombies is actually quite effective. And makes a satisfying splat.

I'm gonna go out on a limb here and say l4d2.
I learned that peasants catch fire easily.