Leaving the singing to the singer

Generally, it's ill-advised for a singer to force audience participation at his or her concerts.  Occasionally, I'll see footage of a singer demanding that the audience sing along and saying, "I can't hear you!" or "Louder!" I'll think, "I know confidence is essential for a singer, but don't press your luck.  Maybe the crowd doesn't want to sing.  Just be happy that they like your music enough to show up for it."