The difference...

...between western and English. A lot of the time, it's a case of never the twain shall meet.

How about a bit of a duel?

This video highlights the differences beautifully.

It also demonstrates something else. These riders are, presumably, both experts. After they switch horses, the dressage rider does slightly better than the reining rider.

I have long held that if you are not sure which side you want to go - it is much, much easier to learn English *first* and I think this video demonstrates that.

It also beautifully shows the difference in self-carriage and way of going. Nicely done.