Continuity mistake: After the "dirtbag" is brought back to the manor and Piper is ragging on him, Piper gets very angry and decides to blow her husband up. Less than a minute later, Cole says "Back away slowly, Leo." Leo says "What?" and Cole says "She's becoming a fury." Then it shows Pipers hands, which now have long black fingernails, but they just suddenly show themselves right when Cole decides to show up and say she's becoming a Fury. When she blew Leo into orbs there were no long black nails. (00:25:35)
Continuity mistake: When Piper is grieving Prue's death in the mausoleum, Leo's hand moves from cupping her face to resting on her shoulder blade between shots. (00:37:15)
Continuity mistake: During the opening, Piper, Phoebe and Cole are in an SUV and going to find a demon. A shot from in front shows that there is no rearview mirror in the SUV, just a white mark on the windshield. When they turn into the parking lot however, the rearview mirror has returned.
Answer: "Hush, Hush, Hush" Paula Cole.