I hate people who can't drive. I know you've said the very same thing, likely about me, but honestly - I don't care. I can drive. I've had two accidents EVER and both were caused by other people. (Technically one was caused by a spider, but we won't get into that.)
When driving down the street there seem to be three types of drivers and at one time or another, we've all been one of these people. Imagine you're going down a three lane... err, lane and riding a horse. It's a nice horse, nothing flashy like those damned Arabians but a sound quarterhorse (Bays and Paints are lovely) with good speed in the straightaway. (Besides, Arabians are expensive and high maintenance. They are high-stung and cost a bundle to fix when they go lame. And they always go lame.) You're riding along when ahead of you in your lane is someone riding a cow.
Now, cows have the potential to be quite fast. Ever seen those bovines stampede? Me either, but I hear it's a sight. I'm a city girl and if ever cows stampede here, I'm going to have some serious issues with the city planners. Anyway, so you're riding along and there's a cow. It's plodding along. Not necessarily a slow animal, but why is it in the horse lane? It's obviously not traveling at the same speeds as the horses. (Unless you've confused a mule with a horse or you're riding a draft of some sort that's older than dirt, you know the ones - they looked like they were frisky three-year-olds but they have dyed manes and are drugged up so they look like they are in shape.)
You look around, thinking to pass the cow behind the next thoroughbred to zip by you, but instead you see another cow traveling just fast enough that you can't slip past. Or worse, it's a sheep. Sheep travel in long lines behind a cow that seems to be moving quickly to them. Sheep are stupid that way. They will follow whomever is in the lead, but they don't have the discernment to follow behind a horse that will get them where they are going in a timely manner.
So you and your excellent steed are stuck in traveling hell. Cows and sheep everywhere you look. This is my experience driving on the interstates in the Baltimore/DC Metro area. In Virginia, there are a lot of people either riding cows or pushing along nags that need to be retired to pasture. In DC, everyone is lost. It's not that big of a city, but seriously - you could wander in circles for days. Plus, they are all on sheep. I'll give Maryland credit, they mostly ride horses there - from nags to racers, but most of them have bad seats and no riding etiquette.
Horses, cows and sheep - God help you if one of them turns up lame.