I expected horses would be able to actually trample people.  
I told this story before, but I'll tell it again because it actually happened.
I remember getting my first horse -- I was sooo excited.  It was a large, well muscled beast that gave a commanding view of the battlefield.  "Now I will be king of tha battlefield, just like cavalry in real life!"  I mounted up and sprinted towards the first enemy I saw.  The hooves were thundering and my heart was racing.  I had the enemy 2h dead in my sights going at full speed -- and he was just standing there!  "LOL that noob!  I'm going to run his ass over!"  Images of shattered bones and broken bodies flashed before my imagination as I got closer and closer to my prey.  The anticipation was exhilarating!  I thought about trying to hit him with my sword as I approached, but as a new player I figured I should just start with basics and trample his ass back to the stone age.  Here it comes...!!!!
That's when he jumped in the air and swung his 2h at me.  I died in one hit and my horse ran off without me.  Needless to say I was pretty damn disappointed.
After a few more tries with similar results, I decided to speak my mind.
"Cav kind of sucks in this game, doesn't it?" I typed.
"yep" was the reply.