I'm with you. I always remove the bucket on level concrete in the same place in my garage, and it's an absolute crap shoot whether or not it will take 2 minutes or ten or twenty, though most of my problems come when I'm putting it back on. Actually, the easiest time I ever had was the first time...since then, it's hit or miss. I've been using the bucket a lot so it comes on/off once a week when I mow, and I'm starting to dread it. Taking it off, sometimes it doesn't want to slip off the pins (not the pins that slide out, the welded pins on the bracket on the tractor)...sometimes, in my manoevering, the hydraulic cylinders end up pushed out to different lengths when trying to put it back on, which becomes a very tricky situation.
I've been tilting the bucket, then dropping it down to raise the tractor while tilted, removing the pins, then uncurling the bucket to land it on the stand and pull it off the tractor. A slight difference in techniques but maybe I'll try raising the tractor with a level bucket?
Good luck. I don't care what anyone says, it's not always as easy as it looks.