The worst I've ever seen is an akhal teke dam clydesdale sire. It had the slender long body of the akhal teke and a wicked heavy head with huge feet. I felt so bad for the poor thing. The woman paid a ton of money to get the mare shipped over and then bred her to a poor excuse of a clydesdale. The mare wasn't all that good looking either. Tons of conformation issues all over the board with those ones. I don't think the baby lived all that long only about 10-12 years. Some crosses should never be made.
Show me a horseman who hasn't fallen and I'll show you a man who has never truly ridden.