Just because something is popular doesn't mean its high quality.
For example, "It's Chico Time" got the UK Number 1
As did "Mr. Blobby", "The Theme from Teletubbies" and "Bob the Builder"
Mamma Mia is bum gravy of the highest order. Hideous film, linking dispirate songs over a lose, passe script.
Its no We Will Rock You... But its close to being that bad.