One of my players in a 1Ed campaign introduced his hard-drinking, cross-dressing, homosexual winged folk (race from Dragon Magazine) Fighter-mage.
It wasn't that his PC was gay. I have no problem with that. It wasn't the cross-dressing, either (the PC illustration included mascara, eye-shadow, and a beauty mark).
It was that he played the PC as an over-the-top, campy, nymphomaniac/slut who hit on all the other PCs.
And the monsters.
This was a weeeeeeeeeeeee bit disruptive.
On the other hand, I'm occasionally guilty...
I was a playtester for a GURPS Vampire. I hate GURPS, but the game group I was in at the time were all buddies of the guys at SG. We had been playing a LOT of it, so I finally rebelled.
In a calculated effort to cut short the campaign, I created Major Mosquito- a powerful Brujah who, in life, had been a private detective. The process of being "brought over" had driven him insane. His powerful but now warped mind did the math: super strength + super speed+ nigh invulnerabilty = super hero. He used his "Crime Straw" to suck the blood of the guilty. His costume included chainmail and he toted a crossbow because of certain other bad guys he had encountered- and he got around town in his 1968, black Mach 1 Mustang...but patrolled the area (once he arrived) on his BMX bike with cards in the spokes (to get the "mosquito buzz" effect). The Brujah thought he was so crazy he had to be Malkavian...
The odd thing was, as outre as the character was (yes, based on the Tick), he actually formed a focal point for the campaign. With all the other PCs constantly manipulating him to take out "hard targets," it was almost like playing a Paladin.