Many times in shaas we find Amoraim saying כדאמרי אינשי or היינו דאמרי אינשי. Usually its brought as a proof for something said but once in a while it is used as a question והא אמרי אינשי.
Are the baalei shaas quoting anyone in particular? Were these just folk sayings? Should the colloquial expressions really play such an important part in deciding halacha, either to prove or disprove it?