The worst I've done is a cold calling job from home. This was a couple of years ago, and I think one or two others from this forum got the job, too. The system automatically called people and I had to read a dodgy script about buying food baskets from a farm. It was soul destroying, and I hated every second of it. I couldn't blame the people on the other end of the line for being annoyed because I'd be the same.
All in all, I lasted about 2 hours on the job and then quit. I just couldn't do it, and I told myself I'd never take another job like that again.