Here's one:
When Animal Crossing came out on the GameCube, I was really looking forward to playing all the NES games it featured as unlockable bonuses.
At the time I had a roommate who was also into video games, but not quite as much as I was. We played a ton of FIFA (he's from Brazil and loves soccer), but he'd also play Animal Crossing - a testament to its addictive qualities.
The game rewards you for doing things which help other animals in your community. Chores, gift-giving, letter-writing, etc. If you do something to anger another animal, they can stay angry for a small time, too.
Well, once, while playing, I figured out you could hit other animals in the face with your shovel. Naturally, they don't like it very much and will walk around in a huff if you do it repeatedly. I had done this. I walked up to a particularly friendly bear, "Teddy," who lived just to the west of my house and smacked him about 12 times in the head.
He walked around with those little black clouds over his head and wouldn't talk to me after that. So I thought "Ahh, why not write him an apology letter?" You see, I had heard somewhere that using keywords in your letters could trigger the game's karma system to reward you with rare gifts. All I wanted was cool NES games for my pad. So I wrote Teddy a small note containing what I though would make good keywords like "sorry" and "please."
Dear Teddy,
I'm sorry I hit you in the head with that shovel.
Please forgive me.
Sincerely,
Cledus(me)
About a week later, my roommate was playing the game and I was there watching and eating my dinner. He wanted to visit my town to see what was for sale at my town's store. While walking to the store, who should he run into but my pal Teddy! He engaged Teddy in conversation. And then it happened.
Teddy asks him something like, "Hey do you know Cledus? He writes such nice letters. Look!
At this point I was beginning to become a little nervous.
Then the damn bear shows my roommate the letter. My roommate begins reading it out loud and with each word, his laughter began breaking through. By the end of the very short letter, he was howling and slumped over on the couch. "That's so gay!!" Oh, my God, THAT IS SO GAY!!!" "HAHAHAHA, That's HILARIOUS!!!"
I had no idea the other animal residents showed letters you wrote to other players. I tried explaining my reasoning with the keywords, the letter-writing, the NES games. I couldn't even squeeze a word in through the laughter.
I guess Teddy got his revenge after all.
The irony? I don't even think keywords reward you with anything like NES games. I went through the embarrassment of writing letters to teddy bears for nothing.