graeme_p - 11:31 am on Oct 6, 2013 (gmt 0)
Its perfectly possible for someone to be intelligent in one area of life, but act idiotically in others.
People are not willing to learn enough to use a computer safely. Its like driving a car without learning to drive (except the consequences are, at least, rarely fatal).
In your friend's case what he needed to know is
1) that email is easy to fake.
2) Be suspicious of unusual attachment types, or ones that are not suitable to the purpose (e.g. a zip file containing info that could easily have been in the body of the email).
Not difficult to understand.
On the other hand, the email client and OS are often to blame as well - its far too easy to hide attachment types, open attachments without any warning of what application is opening them (where its something suspicious) etc.