Sometimes the answer is to be found with the spectators. Some are just to darn tired to clap or to laugh or whatever. Sometimes it is not your fault. Most pros will tell you that the spectator must never be made the guy responsible for killing the show. Well, most often you can get around the issue by waiting. In our case people don't applaud after you made ends end and middle of the rope switch places. Usually they do. But now they don't. LET THE AWKWARD SILENCE SINK IN. They will applaud because they feel uncomfortable with the silence and need to fill it themselves because you don't do it.
And that might actually loosen up the audience so the rest of the show runs smoothly. If it happens again, you can start filling the gap with a corny joke: "Looks like you see this sort of thing every day." Now they should get the message.
Maybe, just maybe they are just tired. Or maybe they don't like you or magic. And here is why! People gather in groups of shared interest. Those are called friends. A party usually has a lot of friends in one place. They are friends not just because they share the same interests, but also because they think about stuff in similar fashion.
So if you have bad luck, you run into a group which doesn't like going crazy mad every time you make a card come to the top of the deck. Maybe they don't like your look. Maybe you look like those Ellusionist magicians. Maybe they wan't you to get a hair cut and a real job.
It's their fault your show is ruined, but them must never be called out on that. But know that deep inside your show was a good as always. Don't let a bad experience let you down. Sometimes it's the audience's fault.
So I wanna wish you a Merry New Year. (or whatever you say in order to be politically correct)
Have fun with your gig tomorrow!
What? You don't have one tomorrow.... then you're not a pro! ;)