What do you think is the hardest tradeskill to level in World of Warcraft? Skinning has to be one of the easiest of course... but leatherworking is quite hard on the other hand.
The two professions reported to be the "worst" -- both in terms of leveling and overall usefulness -- are leatherworking and engineering. Leatherworking from 350 up is a giant pain, since you need rare patterns, and you don't make a lot of money from LW unless you get hard-to-find epic patterns. Engineering requires a lot of rare materials and is just largely useless. However, on the pain-to-level scale, nothing beats fishing. I would seriously rather beat my head against a wall than fish for more than five minutes these days. Admittedly, it doesn't cost money, but the cost in brain cells is far too great.
