Dean Johnson shares this riff:

The most under-utilized word in the English language is ‘so’. It’s liberal use would signal tolerance and the grasping of opposing ideas. While I don’t have to agree with it, I should understand it. As in "Dean, I think you are the dumbest sumbitch on the planet!". One proper response is "so?". It’s not as if the person’s opinion is likely to matter to any great extent. I’m pretty sure that I am not the dumbest person on the planet, as those people were driving on the street in front of me this afternoon…