Pioneering is probably my favorite, stripping for coal or oil locations and pipelines too. Most any dirt job is cool unless the dozer is way too small for the job. Pushing lots of snow is way cool. Forestry work I generally like, though not in mucky underfoot or underwater conditions. Hate pulling those tow cables by hand thorough the muck.
Not crazy about pushing in rock anymore, dislike ripping really hard rock.
Punching scrapers is good, but don't like the fast-paced big production spreads anymore. One pushcat and three to six pans is alright. A big spread with 30 651's, 12 641's, 25 631's, 6 D9 pushcats and a host of support iron is fun to watch, not so fun to be part of.
Really dislike reclamation work pushing dirt up long steep slopes, then having to track it in. Boring! Cat and pan work is neat in good dirt, don't see much of that anymore.
Not crazy about fine grade work with small dozers either. Backfilling around basements or foundations for example. Grade stakes are just targets of opportunity.
Punching fires is about the worst besides cleaning up spills in a steel mill. Ya feel like a smoked cigar all day and smell worse. In the mill, there's a better than even chance you will become the fire. Did I mention working in a landfill? About a tie there for being at the bottom of the list.
Fact is, if it's not 400 horsepower or above with a nice air-conditioned cab, I really don't want to fool with it anymore. Getting too old I guess.