Poppa is on the money. It is rare that two people who have never met will have real chemistry after only seeing eachother twice. But if the guy does not feel himself as being attracted to his date, he will likely not tell the Shadchan this outright.
Soon, when the word “chemistry” becomes synonymous with “attractive”, people will need to come up with a new word to express why they do not wish to see their date again. Perhaps people will tell their Shadchan that they did not feel “synergy”.