One lesson everyone should be learning by now (and boy, is it hard to get people to go along with me on this) is to use public key encryption wherever possible for any emails you wouldn’t want your kids/parents/boss/spouse/neighbor/dog/etc to see. You wouldn’t mail a confidential letter without an envelope, so why treat email any differently?

There are all sorts of ways to implement it that are free and easy. It just comes down to getting people to understand why it’s good practice.