[tiord]

I think it really depends on the context, and of course on what the remark is. I am not sure I understand what do you exactly mean by "bad remark". IMHO, in addition to what superimposition wrote below, you should evaluate if the remark (comment) stands or not, if it is well argumented, and if you can learn something from it. If yes then learn fro,m it, if no then give an argumented response. IN any case, be polite and curious.