Rye, when I saw the title of this thread, I immediately thought "I'm going to post for once, just so I can say how Avril Lavigne butchered my all-time favourite song."
Then I thought to post about her abomination of a Metallica impersonation too.

They are truly the worst covers of all time.

An Honourable Mention should go to Britney Spears' mockery of Joan Jett's "I love rock and roll" too.