I did retirement home training and used to think it was a sweet job. Then I got in the business and underestimated how demoralizing it was as they give you the easy elders in training while the others make you, or at least me, really think of the fact the job just amounts to an unkarmic freebie.
I once saw a video report on bullshit jobs, where they also interviewed a researcher into how much value is gained or destroyed by various professions.
They said that for every £1 (the researchers worked in the UK) given to marketing executives, that society suffered £11 in lost value.
ETA: The video in question (Dutch, with a few local English bits)