Pretty much all my characters are gay and male, like me. But while I am shy, reserved, and unassertive, the characters I rp best and enjoy most tend to be bossy, temperamental, and brazen. Usually flawed but well-intentioned. Usually manipulative, but sometimes openly so and honest. Usually brave, but sometimes more socially brave and sometimes more physically brave. Usually smart but tunnel-visioned; i.e., just smart enough to get into trouble. Character A is Slytherin me. Character B is Gryffindor me. Etc.

A person who rps with me a lot can probably come up with an intuitive image of my personality on the whole. But certainly not from a mere profile of my character. And even people who rp with me a lot often tend to get things wrong, like those who suspect I am a girl playing a guy just because I like scenes that focus on relationships and how our characters' actions risk or strengthen them.

EDIT: Of course, I should also add that were I a Congressman, I'd fully expect to be attacked for any hyperbolic, hurtful, or ridiculous comments I make OOC while playing in a public forum such as an online game. Being in an alternate ego isn't a good excuse to let loose and be an asshole.