First is cut form of "what do you think that"/"how do you rate/apricate that", often used for asking condition of a man after some event.
The second is exclamation, interjection with denial. Often used after "нет" (no) and with conjunction да (but). It allows you to immediately determine the attitude of the speaker to speach that he heard or rarely action that he see by accompanying intonation, but it isn't a parasite of speech.