Christina Aguilera's 'Master Class' trailer...

Christina Aguilera offering a "master class" in singing?!?! Don't even get me started on that one.
She clearly has chops and can sing her peers out the water but she strains and oversings quite a lot. I hate that. It has always baffled me how someone with such extensive range doesn't know how to bloody sing! Oh, and someone needs to give her a master class on how to release an album, for crying out loud.