"Stop hitting your brother!" As the words came out of my mouth for the fifth time and the eraser came down once again on the brother's head while they both giggled, even I realized that it wasn't working.
My fellow soccer coach had brought his youngest children to practice and they were supposed to be sitting quietly on the sidelines while their sister played soccer. As two very active boys, it wasn't meant to be and I thought I was helping by getting them to stop hitting one another at least. But this was fun for them and the fact that I wanted them to quit made them want to do it even more.
I had to change tactics.
So at first I ignored them and after they lost their captive audience, they stopped. I knew I had seconds before they came up with some new antics so I started asking them questions about themselves. Eventually we moved on to "I Spy" and "guess which animal I am thinking". THIS worked much better than asking them to stop hitting one another.
Kids and horses are not all that different.
When your horse is marching through the bit and insisting on his own tempo, you could pull back and fight him but a more effective approach would be to replace the bad behavior with good. For example, bringing him into a nice bending circle or asking for an increase in tempo beyond what he wanted.
A few years ago I was working on getting Golly comfortable trail riding on his own. He was great with groups but got fidgety and started jigging when out on the trail on his own. It being difficult to make circles on the narrow trails and realizing that simply asking him to slow down was not going to work, I took a different approach. Each time he started jigging I asked for a trot. After a bit of trot we went back to walk and tried again. Jigging again? Trot again. Trotting without me asking? A few strides of canter was the answer. Each time coming back to the slower gait to give him another chance after a few strides. He is essentially a lazy horse so this approach worked great with him. Eventually he determined that it was easier to just walk at a lazy pace.
Of course this wouldn't work with a hot horse -- you'd be galloping home eventually completely out of control! Each horse is going to have their own version of "good behavior" to replace the bad. You know your horse and will know what will work for them.