I first had a phone screen with the recruiter which went fantastic. He was energetic and informed me that my background was a perfect fit for the position they were trying to fill. After the call it took 2 full weeks to scheduled to speak to the hiring manager. During that time I was continually told they were excited about me and were not expecting to like someone so quickly.
Then came the interview with the hiring manager. This was when everything turned negative. He was 10 minutes late to the 30 minute call. Did not ask any technical questions and seemed to be in a rush to get off the phone. He then ended the call at the 30 minute mark exactly.
The next day I was then notified they would not be continuing because my background did not fit what they were looking for after I was repeatedly told otherwise. I even followed up to try and learn what I could do better or what changed but was never responded too.
My recomendation would be to make sure you are upfront with your candidates. If they really aren'y qualified or a good match don't tell them they are! Also If you happen to already have a candidate in mind or know you will not be hiring the candidate just come out and tell them. Its better not to waste either parties time.