Amby dear, that's the name of business. You can't make everybody happy but you don't go on public humiliating your customers. Remember they are the one who pays your bills. I am not saying that you suck up to them, but you gotta own up to your mistakes too. You should take those feedback as constructive criticism. Think positive. Remember grass is not always greener on the other side. If you can't take criticism from your customer, I guess you are in a wrong business.