YOU PEOPLE WHO PUT BRYAN DAVID MITCHELL IN PRISON R FAGITS! HE IS A VERY SWEET KIND RELIGUS MAN WHO LUVS JESUS AN HIS FAMILY AN HE NEVER WOULD HAVE GOT MIXED UP WITH THE WHORE ELIZABETH SMART IF SHE WUNT A YOUNG JEZEBEL WHORE!!!
Or something like:
GOD HATES FAGS!!! GOD HATES AMERICA!!! WE AT WESTBORO BAPTIST CHURCH CALL ON GOD TO DRENCH THIS GOD DAMNED COUNTRY IN A THOUSAND FOOT HIGH TSUNAMI OF BLOOD!!!
It’s actually challenging to get my brain into this gear. I’m glad of that.
“I’ve just caused all of the switches and signals on the track to malfunction.”
What?
Your ideas intrigue me and I would like to subscribe to your newsletter.
And don’t get me started on how the Jews made McCain pick Palin.
No-o-o-o! The Jews made the GOP pick McCain, then Wall Street made McCain pick Palin (who is really a Jew, but pretends to be Christian). The conspiracy is never as simple as it looks from the outside.
Attention, all men! Now organizing CREW – the Committee for the Re-Enslavement of Women! Screw the bitches! Repeal the 19th Amendment! Decriminalize rape!
Why should men be allowed to marry men? I can’t marry my dog.
On a planned parenthood board (not necessarily one linked to Planned Parenthood), specially in one involving members of the Spelling Brigade:
“i want agirl so much!!! all ive had so far are boys n Ive never wanted boys but sroulsy after ate I’m sick and tired of boystuff, kn u rcomend a good sexchoos clink?”
ETA: I’m not sure which preferred gender would be the bigger trainwreck, but the difference would probably not be more than one or two wagons.
Fat people should have their cats declawed
For a GLBT board:
I honestly don’t want to offend anyone by using the incorrect terminology. Do you prefer to be called trannies, shemales, or ladyboys?
Any board at all:
I’m a nice guy. I [2 paragraphs of details supporting claims of niceness] So why do all women prefer to date assholes?
For ATMB:
I’ve been fucking one of the mods. Guess which one!
“Hey, white guys, slavery is legal again. Who would you own? I claim Halle Berry and Beyonce”
Out here:
“Stop whining about the “illegal” Hawaiian overthrow. You pussies could’ve had fought for your beloved nation in 1893. But no, you let some businessmen and a handful of marines walk up without a shot fired. Warrior nation, indeed. What if the American Revolution just consisted of a strongly-worded letter to the King George? We’d still be speaking English, that’s what.”
I had to think about this one. And by “think about,” I mean “read it then was about to post the same thing myself.”
Very nicely done, Asimovian.
We’ve certainly been down, and off, those tracks here.
On one type of poetry board:
i rite from the ~HEART~ and my ~FEALINGS~ and hear is all of them!!!
On another type:
If it doesn’t rhyme, it isn’t poetry.
On a third type:
Rhyme is artificial and I write poetry naturally.
And on another:
Bukowski is the only poet worth reading!
Actually, I think you could get a rise at any poetry board with any one of the above. 
At the SFF.Net private boards:
“I just posted your comments here on my blog to ridicule them. Take a look.”
(Based upon a real incident)
on the SDMB? definitely
“Does Jesus Love Me? If So, How Much?”
Why isn’t this a solution for the “homosexuality problem”? Men having sex with men is disgusting. Women having sex with women is sexy. Everyone knows that. So, lets make it a law that homosexual men have to undergo a sex change!
At their own expense of course, paying for it would be socialism.
“I have gradually realized that over the course of my time here at the SDMB, I have never lost an argument. In fact, I have not made even a single fallacious statement, and I have always remained objective. I suspect this is because I am very self-aware and so I am able to assess my own argument objectively and account for cognitive bias before clicking the “post” button. In possession of an enlightened approach to the search for truth, I am open minded, and inquire as to the veracity of my self-assessment. Does anyone disagree? If so, prove it.”
I’ll skip SDMB ones.
Steam Forum:
Any announcement Steam makes. For example, if they announced, “Tomorrow, we’re giving everyone 10 free games of their choice,” people would complain about it being only ten games or having to wait for tomorrow to get the games.
Fishing related ones:
Largemouth Bass Recipes!
What’s the best color power bait? (Has to be in a fly fishing forum)
This one’s true. I once suggested the members on a fishing forum I moderate should attempt to use some decent English in their posts. Holy crap was there a huge outcry. 