The one horse I ride named Sassy almost sounds like yours. She is really buddy sour, likes to buck/be a twit in the arena, etc...
I couldn't even walk her down the road. So one day I brought my riding crop with, the moment she stopped I firmly asked her to go on and she stood there. So I popped her a few times with a crop, spun her around a few times/back her up/made her sidepass, etc.. She would usually go on after that. If she didn't I gave her a pretty hard smack with my crop and she knew business then. It happened 3 times and she never tried it again. Take off your spurs, and work on moving feet forwards, backwards, sideways, and diagnol.
With the bucking and rearing in the arena, I was taking a lesson with a new trainer and Sassy kept rearing so I asked her what her opinion was of what I should do. So I told her about Sassy and she said just ignore it like it didn't happen and push her on which helped Sassy, I used to really discipline her when she acted up but then it got her worked up and not thinking straight.
For getting your horse to move forwards, backwards, sideways and diagnol I like to do what I call the 'Square of Death'. Set up 4 cones in a square. You can do so many exercises in a square such as:
1) Walk the edges, and at the corners make your horse do a a turn on the forehand.
2) Walk a side, stop at the cone then just side pass over to the next cone, back up to the next cone, and sidepass back over to where you started.
3) Start in the middle of the square and move diagnol to a corner..
Set up 4 cones and incorporate moving forwards, backwards, sideways, and diangol and it really gets a horse thinking! You can even had poles for them to step over or other objects.