When riding a horse, if you collide with non-persistent leaves (naturally-generated, not player placed) - the leaves will break and you will be slightly slowed.

Jump to break leaves directly above you.

I think this is a good solution for people who like riding horses for exploration yet are discouraged to do so because it's infuriating to ride through forests.

Another good solution would be to make horses be able to just walk through leaves when ridden. Or install the datapack that makes trees taller. I like breaking leaves though because it feels nice to create paths through forests.