I think the point being made by Bree123 is not to undervalue your work, but to not be snippy with a client. Being professional in your demeanor, even while being firm about your prices, etc, means others will see you as a professional, even when wacko customers like this one try to badmouth you. that doesn't mean you should ever put up with someone that rants and raves or becomes verbally abusive--but if that happens, it's time to say sorry this won't be an ongoing client relationship, I don't think we will be doing further business. That pretty much says it!