Well this could get lengthy since I have a short attention span and have had more shitty jobs than Geroge Orwell. (That's a lot, look it up.)
But the worst, that's easy. That would be the first two treeplanting jobs I ever went on. This was in BC in '76. The first one, we were clambering around on an extremely steep clearcut mountainside on which the slash had not been moved or burned...the contractor had bid it too low, and after eight days of making about $20/day less camp fees ($100 was a good days pay for planting then, $50 about the minimum standard) we were shut down by the Forest Service for inadequate production. (Silver lining though: the cook on that job was Neal Hellman, a well-known lap dulcimer player and dulcimer-book-writer. There was a specific evening when I tried to jam with them, that Neal and someone else showed me how to play guitar with fiddle tunes---the jiggety jig thing. This was a breakthrough of sorts. Great cook too.)
After that contract folded I went on to another planting job farther north--got sick from planting in the rain too much, ended up wandering the streets of Prince George with a fever of 103, very little money, and a 60-lb pack. Yuck. I did quite a bit more tree-planting, amazingly enough, never got really fast but I ended up going to forestry college and later on was usually the foreman or subforeman, which was a not much better job.
My best job was perhaps doing lake trout fishery field work--mostly creel census on Eels Lake north of Peterborough. They give you a boat and you go out and talk to fishermen, find out what they're catching and offer to clean their fish so you can see what it had for lunch (you get used to this.) They started me out with an 18 hp rental boat, but after I demonstrated some nautical incompetence they busted me down to a 6 hp boat. This was o.k, since I still went out but my boat wasn't fast enough to catch up to anyone else's boat. (Lake trout fishers would much rather troll than talk to anyone) Occasionally I'd find someone bass fishing, but mostly my day's work entailed a leisurely cruise about six miles up this chain of lakes...counting how many people were out there fishing. When I got up to the far end of the lake there was a little island of cedar trees with a nice private clearing in the middle, and I had a chunk of hash about the size of yer thumb...I'd take a little interlude, cruise back, and go home. Now that was a job.
For satisfaction of doing something useful without sacrificing my independent nature though, I like what I do now which is being a small-time carpenter/handyman. Mostly building woodsheds, lofts, decks and stuff like that. It's got rather severe downsides like not enough work and money comes my way, and a minor injury can sideline me, as happened this fall, and I swear I'm out of it for good and going to get a nice dry high-tech job, but then another woodshed to be built shows up--happened today--and I like what I do again. Considering the season, I may include a manger.