Agree with you all, there are tons of sad moments on the show - the girls' mother, andy, prue, piper losing her, etc. - and all of them do seem to surround either Prue or Piper. And I admit, I did feel a cold chill when the door slammed shut and the glass broke at the end of season three, let you with that "Woah. Oh my goah." feeling. And when Paige (who I actually do like because she as there for the girls and helped to take care of them an move Piper on some from the grief that was eatting her alive - in short - me like Paige
) told Piper it was okay to hate Prue I was like, "This is Prue, Piper could never hate her. Be upset sure, but hate she just can't do.", and of course the gravesite when Piper finally broke down I think a lot of us if not all did along with her. Not wondering if some of that performance wasn't Holly herself venting.
And yes, I admit it, when they showed Paige looking at Prue's name I did say out loud, "See, better learn that name. It's who you need to know." meaning I know Paige will never live up to Prue, not exactly anyways, but she's still someone she's going to have to replace and fill in for.
Anyways, really rambling now. Lol.
Sad moments on 'Charmed', yes many.