Speaking up in defence of Welsh ponies everywhere. Like all mountain and moorland breeds, they have both brains and an acute sense of self-preservation. If their human is fair and consistent, the pony will come to trust their human and will work in partnership and with evident pleasure. They really resent being bossed and they appreciate being asked rather than told. Often they work things out for themselves.
But too many ponies are spoiled by inconsistent training and handling - “ahh, isn’t it cute” - and are soured by too many small kids bouncing around, yanking on their mouth and using a stick excessively because small legs aren’t strong enough and being roughly handled by adults because they are deemed to be “little sh!ts”.
Don’t be deceived by their small stature. They require exactly the same training as any other horse. Ground manners are vital as small children don’t usually apply them. Adults can certainly retrain for those. A small adult can ride them as they are strong enough, even a little 13.2, but long reining is more traditional. They are excellent to drive. IME most improve in temperament if a) they have an interesting job to do and b) they like and trust their human.