As we all know, horses can be rather large. Forcing them to cooperate with us would be difficult but coercing them, fortunately, has brought dividends over many thousands of years. Whether you view a horse as a cognitive animal or an animal of flight, it's unique behaviour lends itself to human endeavour.
So why do we still see people yanking at their reins, lashing with the whip or urging with their hips? I've spent a lot of time with 'horsey' friends and have witnessed raised voices and frustrating moments first hand. Endless material, in fact, for the likes of Thelwell!
The problems all come down to a matter of practise, in particular developing the skills of direction and inhibition, which lessons in the Alexander technique can definitely help with. If you can refine a rider's technique then the horse will respond positively.
I've taught many riders over the years and they always learn very easily. So, if you love to ride, my advice is to find yourself an Alexander teacher and saddle up with confidence!