I didn't mind working as a cleaner for about 5 years, when I was younger, so much - it was for private houses, paid well and kept me fit. I think the most soul destroying job I ever had - it was only for a few days - was a temping job sending out a mail campaign: folding flyer, putting in envelope, manually adding a stamp to the envelope, sealing envelope x 5000 or something. I honestly can't remember if I had to write the address the envelope either or if it had been done already. Either way, it sucked.
Another one was watching adverts and having to note the times they were shown and some other data I also can't remember, it was long ago. Transcribing can be soul destroying too if the people who are talking aren't easy to understand
I worked in a college for a while, and enrolment week was pretty intense... A conveyor belt of people - it was hard to give a shit after a while.