A couple things:
1. The instructor was a douchebag.
2. Not all instructors are the same. Some instructors click with certain students, others have styles that click with others.
3. Don't waste your time, sanity and energy boiling over a 2 hr lesson and $120 (or however much it costs). Learning to snowboard is a long, never-ending road, filled with pain, frustration, stagnation, and eventually triumph. 1 lousy instructor will just end up as a blip on a very long shit list, which could include injuries, board damage, collisions, encounters with asshole riders, or god forbid, crappy snow.
4. You need to learn skidded turns. Those are your brakes. You can't do dynamic linked carved backside 1080 triple whatever... unless you do linked skidded turns first. When my legs burn, I stop along the side, take a break, and enjoy the view. Eventually, things will get easier on your body as you get better.
5. You have to learn a lot more than just speed control to get down a blue or black (with any degree of elegance).
6. There is no basic way of getting down a blue or black run without skidding. If there was, they would be basic runs instead of 'expert' or 'intermediate' runs.
7. If you want to stop skidded turns, you're probably going to be doing either carving or maybe hop turning. Neither of them are simple, and you're probably not going to learn to do them overnight.
8. You're allowed to vent, and I think the nice people on this forum will commiserate. But you won't get any better unless you put it down, and get out there and try again.
9. Try taking lessons again, and if you find a good instructor, request him or her again.
10. Most of the time, when I take a lesson, I don't exit the lesson any better than when I went in. But the instructor gives you a framework of thought, and is usually pretty honest about pointing out errors. They also encourage you to tackle runs that you normally wouldn't do, and provide an environment where it's ok to fail and learn. In the long run, lessons helped.