How you feel about the prospective client sitting in front of you isn't the best gauge to determine if she or he is your ideal client or not. Even when it seems as if both of you might be butting heads together, it still is a good idea to ask questions to get to the root of why you are having that conversation in the first place! You might confirm that the deal is indeed dead. You might also confirm that you have other avenues through which you could help the prospect! You can't truly know which way is north or south unless you keep asking questions!