The bad_riding community on LJ has been extremely educational. Understand, the people I rode with were, by and large, pretty sane. A lot of them were stuck-up brats, and they weren't all stellar riders, but for the most part, people didn't do things that were monumentally stupid, and mostly worked with trainers when trying new things/dealing with green horses. This, apparently, is not the norm, at least according to youtube. Let's jump in, shall we?
-Helmets are, apparently, totally optional! Whether you're just hacking out, or whether you're trying to jump your mule over another mule (it exists on video), helmets are totally just a suggestion. (this applies also to footwear, pants, and proper tack)
-The ability to successfully get yourself and your horse over any conglomeration of sticks, milk crates, rocks, and fencing material in your back yard totally makes you a badass grand prix jumper! You should post video montages of it all the time, and scoff at anyone who suggests that you maybe learn what "two point position" is before trying to run your 4-year-old gelding at a 3 foot fence. Barbed wire makes a great oxer, btw!
-Horses are jungle gyms. Climb all over them. Take a running jump onto their kidneys! Try vaulting tricks for the first time in the middle of a field without even a halter on! And, of course, helmets will just get in the way.
-Remember; it is never ever your fault when you fall off! Your horse is always just having a bad day. Your fall totally wasn't because you slam up onto his neck after every jump, nor was it because your seat is basically nonexistant at the canter. Your horse's bucking is totally because she's crazy, not because you're bending her sideways the wrong way around the turns and yanking her in the face over every jump. Again, post many videos of this to illustrate how crazy your horse is and what a saint you are for putting up with it.
-Dressage = bouncing around in a reeeaaaally slow sitting trot, balancing on your hands. That is exactly the same as a passage, guys. Bonus points if your hands are solidified into place- holding your mount's head completely static regardless of its position is "keeping him in a frame."
-On the other end of the spectrum; for an extended walk, or for any hunter/pleasure class ever, the proper place for your hands is somewhere between your crotch and your knees.
-Rearing is a neat trick, you should teach your horse to do it all the time. Also, tying his legs up to trip him into "laying down" so you can sit on him isn't mean or potentially injurious at all, but is actually a fun party game.
-When in doubt, giggle, scream, yell, or squeal. Horses love loud, sudden noises!