I've started using automated workers to minimize my micromanagement (i.e. button clicking!). I noticed that sometimes it seems workers are just standing there doing nothing but the next turn they're off doing something or other. Until that is, every last tile around every last city is improved to the hilt. I had probably twenty workers automated on a medium sized continent, by the 1800's they'd finished improving everything on the land mass and went to wait in various cities for something to do. I started having pollution issues and everytime I had some pollution I'd hit "A" and they'd all rush to clean it up. The rest I ended up joining to a few slow growing cities.
"do or do not, there is no try."