Jimmy Kimmel's 'Mean Tweets' are back, and this time it's another music edition featuring artists like Lady Gaga, Katy Perry, Sam Smith, and Ed Sheeran!

My favorite one came from Psy, singer of 2012's 'Gangnam Style,' mostly because of his response to the mean tweet...see for yourself!

I still can't believe some of the stuff people say online!

(Oh, and in case you were wondering why Sia wasn't facing the camera? Here's why.)