Opening a bottle of champagne will be easier if you chill it in a bucket filled with ice rather than chilling the whole bottle inside the refrigerator. The reason? Chilling the whole bottle would make the whole thing contract squeezing the cork firmly in place. With the neck clinging to the cork, you might not also get that popping sound.
Dipping in an ice bucket would expose the neck to room temperature instead, preventing the neck from constricting the cork and allowing for an easy pop.