Dumbest accent I ever heard is where I grew up (western Maryland). They over-pronounce O's (as in "I'm goe-ing hoe-me"), "roof" is pronounced "ruff", "creek" is "crick", and "wash" is "warsh". At least most accents still have some sort of basis in how the word is actually spelled, instead of randomly adding/changing letters.
I'm in an accent-free zone here in Ohio. Go very far north, south, or east of here and people start sounding weird though.
