Andy from The Jerx (previously) continues to develop the theory of "audience-centered magic" with an excellent post on the deficiencies of snapping one's fingers to mark the moment at which some magic effect is meant to be happening.
His argument is that "When you snap your fingers to make magic happen you're essentially saying, 'Look at me! I'm a magic genie!' That's going to pull the rug out from under any sense that what they're seeing has any real relevance."
What should you do instead of snapping? Pretty much anything.
Do any other goddamn thing you want. You're doing ambitious card? Rub your hands together and hold them around the deck like Mr. Miyagi. Say a prayer. Stare at the deck and sharply inhale after a few seconds. Cast a shadow over the deck a la Michael Ammar (I like to do very elaborate variations on this). Teach your spectator to create an energy ball then pluck it from their hands and smash it into the deck. Set the deck on the table and wait for 2:33 AM (the Devil's hour). Slowly breathe over the deck. Put the deck in the refrigerator for a minute. Extract the "essence" of the deck from the deck on the table, spread through this invisible deck in your hand, and place their invisible selection on top of the invisible deck and then push that essence back into the actual deck.
The Least You Can Do [Andy/The Jerx]