Metallica has canceled tour dates in Australia and New Zealand after the band announced on Friday that vocalist James Hetfield as entered rehab again to address his issues with addiction. The band tweeted Friday "As most of you probably know, our brother James has been struggling with addiction on and off for many years. He has now, unfortunately, had to re-enter a treatment program to work on his recovery again." Fans and fellow members of the rock community including members of Slipknot, Halestorm and more have tweeted their support to the band with the hashtags "papahet" and "metallicafamily". Are you surprised that James Hetfield has entered an addiction treatment program again? Why do you think addiction is so hard to overcome?