"The surgery" is a phrase I hear entirely too often. I know it's not the same for ftm as mtf, but still there's a fundamental lack of understanding when a person insists on certain medical procedures before they will accept your identity. It sounds a little frustrating and scary.
I've learned that the less said the better. Like, tell them who you are now and give them cues how to take it, but not too many details about your own feelings (at least not at first). They'll be uncertain and if you set the tone they'll likely follow.