For a client I once set up an experiment in which those waiting in a movie theater line were greeted by smiling, attractive college students and offered free custom fudge and caramel Wonderbars on silver trays.
Still more of them gathered round in an audience, stuck to the walls, crowding the shelves, perched on the lintel, all of them muttering opinions as the preparations went on they would have baked, not seared, that fish, and salted the cabbage but not the asparagus, and chosen caramel over fudge for the cake.