I don't think this song is as involved as you all think.
My interpretation is simple:
Sia sings about drug addicts and partiers - "For those who've kept themselves jacked up...For those who speed, for those who try to slow their minds with weed...For those who wake with a blind headache"
They rest on Sunday (who doesn't? I know I do) which, to religious people, is the day of rest as yall mentioned earlier, but the "Jesus wept" part means she (and Jesus, obviously) doesn't condone the partying, but "it'll be okay...give yourself a break"
The "guilt...wilt...milk" part still refers to the partiers...they feel guilty for all the crazy things they've done, the drugs and alcohol wilt them, in a sense.
I don't think this song is as involved as you all think. My interpretation is simple: Sia sings about drug addicts and partiers - "For those who've kept themselves jacked up...For those who speed, for those who try to slow their minds with weed...For those who wake with a blind headache" They rest on Sunday (who doesn't? I know I do) which, to religious people, is the day of rest as yall mentioned earlier, but the "Jesus wept" part means she (and Jesus, obviously) doesn't condone the partying, but "it'll be okay...give yourself a break" The "guilt...wilt...milk" part still refers to the partiers...they feel guilty for all the crazy things they've done, the drugs and alcohol wilt them, in a sense.
Simple as that.