It still surprises me how often I see somebody hauling a cow or bull, with head untied, in one of those old-timey open top trailers. They are just asking for an "adventure". We used an open top trailer down on Grandpa's farm 40 or 50 years ago but we always made sure to tie their head down real tight.
All my bulls have been very well behaved, but the meanest bull I've seen was actually at a special bull sale a few years ago. They had a nice looking Brangus all by himself, way in the back of the facility, in a very spacious, high walled pipe & concrete pen. The bull hung out in the middle of the pen and charged with reckless abandon anytime somebody approached the pen. Snot flying, kicking up dust, pawing the ground, bellering and charging up to the pipe walls and butted them real hard. I couldn't believe they had him at the auction. He was the last bull auctioned and the auctioneer just announced to everybody that "this bull just plain don't like any people, so buyer beware". I was surprised to see that he sold for only about $100 less than other nice Brangus bulls that day, all of which were real well behaved. His pedigree was full of Brinks blood and I can only assume that's the reason somebody was willing to take him home.