It's your horse's natural asymmetry.
Now, we are all born as asymmetrical beings
For example, all creatures are left or right handed - in the hands, feet, paws, claws or hooves.
And this of great help for survival.
But it totally backfires the moment we start riding our horse.
If we don't develop our horse equally in body and limbs, all kinds of "bad" things can happen:
- your horse won't yield
- goes against your hand
- develops an underneck
- swishes the tail all the time
- leans in on the circle
- shows grumpy behavior
- has a hollow topline
- the saddles slips to one side all the time
But there is one thing that's certain...