A subtle yet effective way of pointing out someone's stupidity- as they most likely won't even get your reference in the first place (and may in fact think you are laughing WITH them)- without having to be too frank.
You see, an ignorant braying ass "hee-haws" all day long...call 'em out.
"hee haw, Bro..HEE HAW"
The word is derived from the sound that a donkey makes, therefore it is as if one is calling the heehaw a jackass, without actually using profanity.
"What a heehaw!"