My 15.1hh cob mare spooks at everything. I'm worried about taking her to shows in the summer as I can predict clearly what'll happen!
When I ride her out in the countryside with others, She's as bombproof as my old horse, but when I ride her out alone she hates it. When I ride her in the school, sometimes she goes beautifully, and sometimes she can be really bad.
I can never predict what she's going to do next. She loves jumping and hacking out, and yet when I ask her to canter, she tanks off.