Any and all supporters of Ayn Rand and her insane philosophy that tries to make selfishness a noble goal, particularly those who willfully overlook her belief that those who took government assistance are bad people, despite her spending her final years on Medicare and Social Security.
"Did you hear about David? Ever since he read Atlus Shrugged, he has decided that not caring about his fellow man is a worthy pursuit."
"Oh, he's a Shruggalo? How old is he again? Didn't 'fuck you got mine' go out sometime in middle school?"
To ignore something, not let a problem get you. An effective and mature thing to do when its a situation that can't hurt you and/or is beyond your control.
Sam got the vibethat the two co-workers were envious and didn't want to see him do well, but he knew to shrug it off.
Signalling to another via the medium of text the fact you are carrying out an action, in this case, the movement of raising the shoulders, which highlights the point you are basically saying 'I don't know' or 'whatever' but in a non-verbal manner.