I used to work as an attorney before getting into software engineering, and I clearly took for granted that other educated professionals (particular those in a field where precision is required) would write clearly, logically, and succinctly. My expectations have frequently not been met.
It's particularly humorous, as everyone who has hired me has acted like they were taking a big risk because of my non-technical background. Yet, each time, they quickly realize it was a good idea to hire someone with a strong command of the English language and a ruthless attention to detail.
Of course, the technical skills are required as well, but I don't think people appreciate how easy those are to pick up for someone who is capable of reading and distilling voluminous amounts of information in a short period of time.