Any cat "C" airport would be classed as "demanding" as the consequences of getting it wrong would make the airfield/approach, less forgiving. These airports are still within the capabilities of the "average" pilot.
I saw a film years ago of Ag pilots in New Zealand operating off planed ridges with steep almost vertical sides just to name a few examples. Some were bent like a banana, steep slope, taking off into rising ground, etc., etc. An immediate turn would be required after takeoff on some examples. Passengers are not allowed to be carried on those ops. Some of the airstrips in Papua Nugini would follow a close second, if not on a Parr. The pilots who operate from those sorts of "airports" show exceptional skills IMHO and are demanding.